Question

Yan has already finished Three-fifths of the 45 math problems he was assigned today. Each math problem took him 1 four-fifths of a minute to complete. If this pace continues, how much more time, to the nearest minute, will the rest of the problems take him to finish?

Answer 1

Answer:

$\boxed{\sf 18\ problems = 22\ minutes}$

Step-by-step explanation:

Yan has finished = $\frac{3}{5} of \ 45 \ maths \ problems$

Yan has finished = $\frac{3}{5} * 45$

=> 3 * 9

=> 27 problems

Yan has problem left:

=> 45 - 27

=> 18 problems

1 problem = $1 \frac{4}{5}$ of a minute

1 problem = 1.2 minutes

18 problems = 1.2 * 18

18 problems = 21.6 minutes

18 problems ≈ 22 minutes

Answer 2

Answer:

$\boxed{\sf 32 \ minutes}$

Step-by-step explanation:

Yan finished 3/5 of 45 math problems.

$\frac{3}{5} \times 45=27$

Yan finished 27 math problems.

$\sf 1\frac{4}{5} \ of \ a \ minute= 108 \ seconds=1.8 \ minutes$

Yan has $45-27=18$ problems left.

1 problem = 1.8 minutes

18 problems = $1.8* 18=32.4$ minutes

32.4 minutes to nearest minute will be 32 minutes.