Question

simple interest problems
2-10-26
7th grade

1. elbert frank cox was the first black person to receive a phd in mathematics in the united states and in the world. once he got his degree, he borrowed $12,000 to buy a car. he borrows the money at a yearly interest rate of 4.2%. how much interest will he pay if he borrows the money for 5 years? use the formula $i = prt$
2. how much interest would elbert have to pay if he only borrowed the money for 1 year instead of 5?
3. martha lofton haynes was the first african american woman to earn a phd in mathematics. she borrowed $25,000 to buy a car. she borrows the money for 6 years at a yearly interest rate of 12%. how much interest did martha pay for the car? use the formula $i = prt$

Explanation:

Step1: Identify values for Q1

Principal $P=\$12,000$, Rate $R=4.2\%=0.042$, Time $T=5$

Step2: Calculate interest for Q1

$I = P \times R \times T = 12000 \times 0.042 \times 5$

Step3: Identify values for Q2

Principal $P=\$12,000$, Rate $R=0.042$, Time $T=1$

Step4: Calculate interest for Q2

$I = P \times R \times T = 12000 \times 0.042 \times 1$

Step5: Identify values for Q3

Principal $P=\$25,000$, Rate $R=12\%=0.12$, Time $T=6$

Step6: Calculate interest for Q3

$I = P \times R \times T = 25000 \times 0.12 \times 6$

Answer:

1. $\$2520$
2. $\$504$
3. $\$18000$