Martinahas$8010%annually..Howmuchwillshehavein4years? Use the formula i = prt, where i is the interest earned, p is the principal (starting amount), r is the interest rate expressed as a decimal, and t is the time in years.

i=prt

i= 80(.10) *4

i=32

so basically she earned 32 dollars in interest

96 students attend the Chess Club every Wednesday.

800 is 100% of the population. We simply multiply 12% to the population of 800 to get its value.

800 x 12% = 96 students

To check: divide 96 by 800 to get its percentage.

96 / 800 = 0.12 x 100% = 12%

96 students is equivalent to 12% of 800, the school's total population.