Slope from a Word Problem

Bob has $150 in his savings account and saves $40 per month.  Which equation represents the amount Bob has in his account after x months?

• y = 150 + 40

• y = 40x + 150

• y = 150x + 40

A man is climbing down from 100 feet high descending 30 feet per minute.

• y = - 30x + 100

• y = 100 + 30x

• y = 100x + 30

• y = 100x - 30

Sandra has a $20 itunes gift card and spends $3 each month.  Which equation can be used to find how much money Sandra has on her giftcard after x months?

• y = 3x + 20

• y = 3 + 20x

• y = -3x + 20

• y = -20x + 3

A canoe rental service charges a $20 transportation fee and $30 dollars an hour to rent a canoe. Write an equation representing the cost, y, of renting a canoe for x hours.

• y = 30x + 20

• y = 30 + 20x

• y = 50x

• y = 60x

Sonya has $40 in her lunch account and pays $2 each day to eat lunch. Which equation can be used to find the amount of money Sonya has left on her account after x days?

• y = 40 + 2x

• y = - 2x + 40

• y = 2 + 40x

• y = 2 - 40x

Suppose that a bike rents for $4 plus $1.50 per hour. Write an equation in slope-intercept form that models this situation.

• y = 4x + 1.50

• y = 1.50x + 4

• y = -4x +1.50

• y = 4x - 1.50

An airplane 30,000 feet above the ground begins descending at a rate of 2,000 feet per minute. Write an equation to model the situation.

• y = - 2,000x + 30,000

• y = - 2,000x - 30,000

• y = 30,000x + 2,000

• y = -30,000x + 2,000

A plumber charges $25 for a service call plus $50 per hour of service. Write an equation in slope-intercept form for the cost, C, after h hours of service.

• C = 25 + 50h

• C = 50 + 25h

• H = 25 + 50c

• H = 50 + 25c