use rates, the rate a person is working is the reciprocal of the time
working together, they work at a rate of 1/3 job per hour
when two people work together their rates add together
---> 1/h + 1/j = 1/3
---> h = j - 8 (harry takes 8 hrs less than jimmy)
substitute and solve for j
<span><span>1<span>j−8</span></span>+<span>1j</span>=<span>13</span></span>
combine fractions
<span><span><span>j+(j−8)</span><span>j(j−8)</span></span>=<span>13</span></span>
cross-multiply
<span><span>j2</span>−8j=6j−24</span>
<span><span>j2</span>−14j+24=0</span>
Factor
<span>(j−12)(j−2)=0</span>
j = 12
It takes jimmy 12 hours to rake the leaves
A number raised to an exponent is the number multiplied by itself the number of times the exponent is.
The exponent is 3, so this means 0.25 is multiplied by itself 3 times.
0.25^3 = 0.25 x 0.25 x 0.25
The answer would be 20.
How?
7 + 9 = 16
16 + 4 = 20
36 = 2 x 2 x 3 x 3 (Answer C)