Proportion

It costs £1.20 to buy enough chocolate to make 12 cookies. How much will it cost to buy enough chocolate to make 18 cookies?

• 80p

• £1.80

• 60p

It takes 3 workmen 4 hours to dig a hole big enough for the new well. How long would it take 6 workmen to dig the same sized hole?

• 8 hours

• 2 hours

• 6 hours

• 4 hours

For an equation to be directly proportional, it must .......

• pass thru two points

• pass thru the origin

• be positive

• not have a fraction

Y varies directly as x. If y = 12 when x = 15, what is y when x = 20?

• 4/5

• 17

• 16

• 25

n varies directly with c. If c = 24 when n = 18, what is c when n = 22?

• 88/3

• 28

• 66/4

• 24

Which equation exhibits a direct proportion?

• y = 5x - 2

• y = 3/4 x

• y - x = 4

• x = 6

Which equation is not an example of direct proportion?

• y = x

• y = 3x

• y = - 6x

• y = 2/3 x + 5

Upon seeing, "y varies directly as x" we immediately.....

• write down what x and y are

• write down what k is equal to

• substitute into the equation

• write y = kx

Y varies directly as x. If y = 39 when x = 52, what is the best answer for k?

• k = 52

• k = 4/3

• k = 3/4

• k = 39/52