8.9 Use direct and inverse variation  (Page 4/10)

If $y$ varies directly as $x$ and $y=14,\text{when}x=3$ , find the equation that relates $x\text{and}y$ .

If $p$ varies directly as $q$ and $p=5,\text{when}q=2$ , find the equation that relates $p\text{and}q$ .

If $v$ varies directly as $w$ and $v=24,\text{when}w=8$ , find the equation that relates $v\text{and}w.$

If $a$ varies directly as $b$ and $a=16,\text{when}b=4$ , find the equation that relates $a\text{and}b.$

If $p$ varies directly as $q$ and $p=9.6,\text{when}q=3$ , find the equation that relates $p\text{and}q.$

If $y$ varies directly as $x$ and $y=12.4,\text{when}x=4,$ find the equation that relates $x\text{and}y$

If $a$ varies directly as $b$ and $a=6,\text{when}b=\frac{1}{3}$ , find the equation that relates $a\text{and}b.$

If $v$ varies directly as $w$ and $v=8,\text{when}w=\frac{1}{2}$ , find the equation that relates $v\text{and}w.$

The amount of money Sally earns, P , varies directly with the number, n , of necklaces she sells. When Sally sells 15 necklaces she earns $150.

1. ⓐ Write the equation that relates P and n .
2. ⓑ How much money would she earn if she sold 4 necklaces?

The price, P , that Eric pays for gas varies directly with the number of gallons, g , he buys. It costs him $50 to buy 20 gallons of gas.

1. ⓐ Write the equation that relates P and g .
2. ⓑ How much would 33 gallons cost Eric?

Terri needs to make some pies for a fundraiser. The number of apples, a , varies directly with number of pies, p . It takes nine apples to make two pies.

1. ⓐ Write the equation that relates a and p .
2. ⓑ How many apples would Terri need for six pies?

Joseph is traveling on a road trip. The distance, d , he travels before stopping for lunch varies directly with the speed, v , he travels. He can travel 120 miles at a speed of 60 mph.

1. ⓐ Write the equation that relates d and v .
2. ⓑ How far would he travel before stopping for lunch at a rate of 65 mph?