Direct Variation Problems and Solutions

Front

If y = 4 when x = -4, find y when x = 7

Back

y = kx; k = y/x = 4/-4 = -1; y = -1 * 7 = -7.

Front

The amount of money earned on a job varies directly to the number of hours worked. If $70.00 is earned in 5 hours, how much money is earned in 22 hours of work?

Back

k = 70/5 = 14; Money earned in 22 hours = 14 * 22 = $308.

Front

In a direct variation, y=39 when x=3. Find the value of y when x=2.

Back

k = 39/3 = 13; y = kx = 13 * 2 = 26.

Front

If y varies directly with x, and y = 8 when x = -4, what is x when y = -48?

Back

k = 8/-4 = -2; -48 = -2x; x = 24.

Front

y varies directly with x. If y = 12 when x = 2, what is the constant of variation?

Back

k = y/x = 12/2 = 6.

Front

Define direct variation.

Back

Direct variation is a relationship between two variables where one variable is a constant multiple of the other, expressed as y = kx.

Front

What is the constant of variation in a direct variation equation?

Back

The constant of variation (k) is the ratio of y to x in the equation y = kx.

Front

If y varies directly with x and y = 10 when x = 5, what is y when x = 10?

Back

k = 10/5 = 2; y = kx = 2 * 10 = 20.

Front

If y = 15 when x = 3, what is the value of k?

Back

k = y/x = 15/3 = 5.

Front

If y varies directly with x and y = -12 when x = 4, what is y when x = -8?

Back

k = -12/4 = -3; y = kx = -3 * -8 = 24.