Question

Rob spent 25\%25% more time on his research project than he had planned. He spent an extra hh hours on the project.

Which of the following expressions could represent the number of hours Rob actually spent on the project?

Answer 1

5h and (h/0.25)1.25

Explanation:

This means he planned to spend \dfrac{\maroonD{h}}{\greenD{25\%}}\cdot100\%

25%

h

​ ⋅100%start fraction, start color maroonD, h, end color maroonD, divided by, start color greenD, 25, percent, end color greenD, end fraction, dot, 100, percent hours on the research project.

Hint #33 / 6

Because 25\%25%25, percent means 252525 per hundred, we can write it in equivalent forms.

\begin{aligned} 25\%&=\dfrac{25}{100}\\\\ &=0.25 \end{aligned}

25%

​

=

100

25

​

=0.25

​

Answer 2

Answer: 5h represents the number of hours Rob actually spent on the project.

Explanation:

Let Rob planned that he will spend x hours in his project.

According to the question,

He spent 25% more time on his project than he planned.

That is, his actual time = x + 25% of x = 125% of x

Again according to the question,

He spent an extra h hours on his project.

That is, 25% of x = h

`(25* x)/(100) = h`

`x=(100h)/(25)`

x = 4h

Thus, his actual time = 125% of x = 125% of 4h =
`(125* 4h)/(100)` = 5h

Which is the required expression.