Question

14.

Jan spent 3 hours doing homework last week.
She spent 5 hours doing homework this week.
How many more hours did Jan spend on homework
this week than last week?
A. 1 hour
B. 1 hour
D. 11 hours
C. 14 hours

Answer 1

D.
`\mathrm{1(1)/(2)\:hours}`

Explanation:

As it asks how many more, it means plus, plus means addition. So, let find the difference between the two fractions.

This week should be at first, and last week should be after the minus sign.

`5(1)/(4) - 3(3)/(4)`

`\mathrm{Convert\:mixed\:numbers\:to\:improper\:fraction}`

`5(1)/(4) = 4*5=20+1=21\\\\(21)/(4) \\\\3(3)/(4) = 4*3=12+3=15\\\\(15)/(4)`

`(21)/(4) - (15)/(4)`

`\mathrm{Subtract\: the\: numerators,\: not \:the \:denominators.}`

`(21)/(4) - (15)/(4)\\\\21-15=6`

`(6)/(4) \\\\\mathrm{\underline{Simplify:}}\: \bold{1(1)/(2)}`