Direct Variation 2

Front

What is direct variation?

Back

Direct variation is a relationship between two variables where one variable is a constant multiple of the other. It can be expressed as y = kx, where k is a non-zero constant.

Front

If y varies directly with x and y = 132 when x = 11, what is the constant of variation (k)?

Back

k = y/x = 132/11 = 12.

Front

If y = 12x, what is the value of y when x = 17?

Back

y = 12 * 17 = 204.

Front

What is the equation of a line that passes through the origin and has a slope of 7.5?

Back

y = 7.5x.

Front

If the price of hamburger varies directly with weight, and 3 pounds cost $6, what is the cost per pound?

Back

Cost per pound = $6 / 3 = $2 per pound.

Front

How much will 10 pounds of hamburger cost if it costs $2 per pound?

Back

Cost = 10 pounds * $2/pound = $20.

Front

If Daniel received $55.35 in interest on $1230, what is the interest rate per dollar?

Back

Interest rate = $55.35 / $1230 = 0.045 or 4.5%.

Front

How much interest would Daniel receive on a $2000 deposit if the interest rate is 4.5%?

Back

Interest = $2000 * 0.045 = $90.

Front

What is a unit rate?

Back

A unit rate is a comparison of two different quantities when they are combined together, expressed as a quantity per one unit of another quantity.

Front

If a car travels 240 miles in 3 hours, what is the unit rate in miles per hour?

Back

Unit rate = 240 miles / 3 hours = 80 miles per hour.