Can you recall the unitary method in mathematics? These math riddles (with answers) will help you recall!

Math riddles are not only fun but can also be a great source of learning if they help us recall some essential mathematical concepts we learned in school. One such concept was the unitary method, which is used in many aspects of our everyday math application to real-life situations.

Ready for the riddles? Read on!

Math Riddle 1:

If 24 painters work for 7 hours a day, to paint a house in 16 days. How many painters are required to work for 8 hours a day and finish painting the same house in 12 days?

Math Riddle 2:

11 potters can make 143 pots in 8 days. How many potters will be required to make 169 pots in 4 days?

Math Riddle 3:

A car traveling at a 140 km/h speed covers 420 km. How much time will it take to cover 280 km?

Math Riddle 4:

“A” finishes his work in 15 days while “B” takes 10 days. How many days will the same work be done if they work together?

Where did the snail come from? Find the hidden snail in this optical illusion image!

ANSWERS:

Math Riddle 1:

If 24 painters work for 7 hours a day, to paint a house in 16 days. How many painters are required to work for 8 hours a day and finish painting the same house in 12 days?

Answer: 28 painters!

Explanation:

We know that

24 painters working for 7 hours paint a house in 16 days.

1 painter working for 7 hours paints a house in 16 × 24 days.

1 painter working for 1 hour paints a house in 16 × 24 × 7 days.

Let the required number of painters be x, then;

x painters working for 1 hour a day paint the house in (16 × 24 × 7)/x days

x painters working for 8 hours a day paint the house in (16 × 24 × 7)/(x  ×  8) days

However, the number of days given = 12

As per the problem;

(16 × 24 × 7)/(x × 8) = 12

2688/8x = 12

8x × 12 = 2688

96x = 2688

x = 2688/96

x = 28

Thus, it is clear that 28 painters working for 8 hours a day will finish the same work in 12 days.

Math Riddle 2:

11 potters can make 143 pots in 8 days. How many potters will be required to make 169 pots in 4 days?

Answer: 26 potters!

Explanation:

We know that,

11 potters can make 143 pots in 8 days.

1 potter can make 143 pots in 8 × 11 days.

1 potter can make 1 pot in (8 × 11)/143 days.

Let the number of potters needed to be x, then;

 x potters can make 1 pot in (8 × 11)/( 143 × x) days

x potters can make 169 pots in (8 × 11 × 169)/(143 × x ) days

But the number of days given = 4

 According to the problem;

(8 × 11 × 169)/(143 × x ) = 4

14872/143x = 4

572x = 14872

x = 14872/572

x = 26

Thus, 26 potters are needed to make 169 pots in 4 days.

Math Riddle 3:

A car traveling at a 140 kmph speed covers 420 km. How much time will it take to cover 280 km?

Answer: 2 hours!

Explanation:

Firstly, we have to find the time required to cover 420 km.

Speed = Distance/Time

140 = 420/T

T = 3 hours

Applying the unitary method,

420 km = 3 hours

1 km = 3/420 hour

280 km = (3/420) x 280 = 2 hours

Math Riddle 4:

“A” finishes his work in 15 days while “B” takes 10 days. How many days will the same work be done if they work together?

Answer: 6 days!

Explanation:

If A requires 15 days to finish his work then,

A’s 1 day of work = 1/15

Similarly, B’s 1 day of work = 1/10

Total work done by A and B in 1 day = 1/15 + 1/10

Taking LCM(15, 10), we have,

1 day’s work of A and B = (2+3)/30

1 day’s work of  (A + B) = ⅙

Therefore, it can be concluded that A and B can finish the work in 6 days if they work together.

Brain Teaser: Guess The Names Of These Three Countries And Prove Your Smartness!