Question

Mr.Williams physical education class lasts 7/8 hour if instruciton is 1/5 how many minutes are not spent on instruction?

Answer 1

= 7/8 − 1/5

= ((7 × 5) − (1 × 8)) / (8 × 5)

= (35 - 8) / 40

= 27/40

= 27/40

SO, 27/40 minutes are NOT spend on instructions.

Hope I helped:P

Answer 2

Answer

Find out the how many minutes are not spent on instruction.

To prove

Let us assume that the numbers of hours Mr. Williams is not  instruciton be x.

As given

$Mr.Williams\ physical\ education\ class\ lasts\ \frac{7}{8}\ hour\ if\ instruciton\ is\ \frac{1}{5} .$

Than the equation becomes

$x = \frac{7}{8} - \frac{1}{5}$

L.C.M of (8,5) = 40

$x = \frac{7\times 5 - 1\times 8}{40}$

$x = \frac{35 - 8}{40}$

$x = \frac{27}{40}$

$x = \frac{27}{40}\ hours$

As 1 hours = 60 mintues

$Now\ convert\ \frac{27}{40}\hours\ into\ mintues.$

$= \frac{27\times 60}{40}$

= 40.5 mintues

Therefore in 40.5 mintues Mr. Williams not spent on instruction .