Mary borrowed $700 from a bank for 3 years and was charged simple interest. The total interest that she paid on the loan $42. As a percentage, what was the annual interest rate of her loan

2 %

Step-by-step explanation:

Money borrowed, Principal, P = $ 700

time of investment, T = 3 years

Total interest paid, Simple interest, S.I = $ 42

Let the rate of interest is R.

Use the formula for simple interest.

By substituting the values

4200 = 2100 R

R = 2 %

Thus, the rate of interest is 2%.

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.