## Friday, January 17, 2020

Mathematics helps us to solve our daily life problems. Our day will not pass without solving many of the mathematics problems and without doing math calculations. Today I am going to post some of the real-life problems which can be solved by mathematics. Many of these problems we may have come across in our daily life.
Try not to use a calculator while solving these math questions. It will be great if you can solve these problems in your mind without even using a pen or pencil. These math problems require knowledge of basic mathematical operations. Answers to these Math riddles are given at the end of this post. Please do put your answers in the comment section of this post.

Q1. Sudeep walks at 6km/h for 3hr and 10km/h for 5hr. What is his average speed?

Q2. If the sum of two numbers is 7 and their product is 12. Find the numbers?

Q3. How many multiples of 5 lies between 12 and 254?

Q4. The ratio between the speeds of two trains is 8: 9. If one train runs 720 km in 9 hours, then what is the speed of the second train?

Q5. If a person bought a TV for Rs. 35,000. and sold it after two years for Rs 27000. Find the loss or gain on his deal?

Q6. Rahul’s mother is 25 years older than him, the product of their ages 5 years from now will be  350. Find their present ages.

Q7. Find the least number which is exactly divisible each of the numbers 12, 16 and 24.

Q8. One litre of petrol costs Rs. 30. What is the cost of 35 litres of petrol?

Q9. Find the area of a square whose each side is 14m.

Q10. An aeroplane covers 5456 km in an hour how much distance will it cover in 5 hours.

Do try solving some more Mathematical Puzzles as mentioned below
List of Maths Puzzles and Brain Teasers

1. Easy Mathematical Brain Teasers with answers: These are easy Maths puzzles for kids and teens.

2. Math Logic Brainteasers for high school students: These are Mathematical Puzzles which will also require your Logical ability to solve these successfully.

3. Fun Maths Number Brain Teasers for Kids with Answers and Explanation: These are fun Maths Number Brain Teasers which are represented in Puzzle Images. Do check out how many of these you can solve without looking at the answers.

4. Quick Out of Box Thinking Riddles with Answers: After solving Mathematical Puzzles, its time now to think out of box solving these lateral thinking Puzzles.

Hidden Answers to these mathematical problems are given below. Do select the text between the numbers to watch out for the corresponding answer.
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A1. 2 km/h
Average speed = total distance / total time
Average speed = 10+6/8= 16/8
Avg speed  = 2km/h

A2. x=3,4.  y=4,3

X+y=7, ....(1),
XY= 12, x=12/y , substituting value of x in (1) we have.
12/y+y= 7
12+y²=7y
y²-7y+12=0
y²-4y-3y+12=0
y(y-4)-3(y-4)=0
(y-4) ( y-3) =0
Y =4, y=3 and x=3,4.

A3.   48
The first number that is multiple of 5 between 12 and 254  = 15,
Last number that is multiple of 5 between 12 and 254  = 250.
So here ,
a  ( initial term)= 15 ,
an= 250, d ( common difference)= 5 according to A.P formula
an= a+ (n-1)d

250= 15+(n-1)5
250-15=( n-1)5

235 /5 = n-1,   n-1= 47

n=47+1=48, Hence there 48 multiples of 5 that lies between 12 and 254,

A4.   90km/h

Speed of first train / speed of second train = 8/9
720 /9/ speed of second train = 8/9
80/ speed of second train = 8/9
Speed of second train= 9x80/8= 90 km /h.

A5. Loss= 8000

Cost Price (C.P) of TV=   35000
Selling Price (S.P) of TV= 27000

We know if C.P > S.P its a loss
Therefore Loss= C.P- S.P= 35000- 27000= 8000 RS.

A6. 5 and  30

Let us suppose Rahul’s present age = x
Mother’s age      =   x+25

Five years from now, Rahul age     =    x+5
Mother age =  x+30

x²+5x+30x+ 150 = 350
x²+35x+150 = 350
x²+35x -200 =0
x²+40x-5x-200=0
x(x+40) – 5( x+40)=0
x=-40, x=5, Taking only positive value , we have

Rahul age is 5  years and the mother’s present age is 30 years.

A7. 48

Least number divisible by  12, 16 and 24.= L.C.M of  12, 16 and 24= 48.

A8.  1050

Cost of One liter of petrol = 30
Cost of 35 liter of petrol     =  30x 35=  1050

A9. 196 sqm

Side of square = 14m
Area of square = side x side
Area= 14x14= 196 sq m

A10.  27280 km
Distance covered by aeroplane in one hour = 5456 km
Distance covered by aeroplane in 5 hours  =  5456 x 5
= 27280 km

#### 4 comments:

1. The sum of 3 and 4 is -3?

1. You are right. Sum of 3 and 4 is 7. We have corrected the puzzle statement. Thanks for your inputs.

2. Please check your answer to the question 4. I think the speed of the first train is 90km/h therefore the speed of the second train cannot be 90km/h.

1. You are right. There was one mistake in the statement which was making the speed of first train as 90 km/h. I have changed the statement of make it correct which will lead to the speed of the first train as 80km/h and therefore the speed of the second train will be 90 Km/h.
Thanks for posting your comment and helping us to correct the error in these puzzles.

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