Percentages and Word Problems Flashcards

An elevator pit is 4 feet deep and must be increased to 5.5 feet. What is the percentage increase in pit depth?

Answer: 37.5%

(5.5 − 4) ÷ 4 × 100 = 1.5 ÷ 4 × 100 = 37.5%.

A parts invoice shows: bearings $240, cable $580, controller $1,200. The company pays 65% and the customer pays the rest. How much does the customer pay?

Answer: $707.00

Total = $2,020; customer pays 35% = 0.35 × $2,020 = $707.00.

A 3-phase motor draws 18 amps normally but surges to 27 amps at startup. What is the percentage increase during startup?

Answer: 50%

(27 − 18) ÷ 18 × 100 = 9 ÷ 18 × 100 = 50%.

A contract earns a 3% commission on a $94,000 installation. What is the commission amount?

Answer: $2,820

3% of $94,000 = 0.03 × $94,000 = $2,820.

A technician works 40 regular hours and 6 overtime hours. Overtime is paid at 1.5× regular rate of $36/hr. What is total gross pay for the week?

Answer: $1,764

Regular: 40 × $36 = $1,440; Overtime: 6 × $54 = $324; Total: $1,440 + $324 = $1,764.

A city requires elevators to pass inspection 90% of the time on the first attempt. Out of 150 inspections, how many are allowed to fail initially?

Answer: 15

10% may fail; 10% of 150 = 15 elevators.

A counterweight saves 35% of motor energy by offsetting the car weight. If the motor normally uses 900 kWh per month, how many kWh does it use with the counterweight?

Answer: 585 kWh

900 × (1 − 0.35) = 900 × 0.65 = 585 kWh.