nathan and steven stacked boxes on a shelf. nathan lifted 13 boxes and steven lifted 15 boxes. the boxes that nathan lifted each weighed 12 lb more than the boxes steven lifted.
let s represent the weight of the boxes that steven lifted.
what expression represents the total number of pounds nathan lifted?
a. 13(s+12)
b. s + 12
c. 15(s+12)
d. 12(s+13)

Imogene invested $8,000 in a bank account that pays 8 percent simple interest at the end of each year. her friend invested the same amount in stocks where the growth of the investment is represented as 2,000 times the square root of 2 less than the time lapsed in years. if y1 and y2 represent the amount earned in dollars and t is the time lapsed in years, which system of equations correctly represents the situation?

Abouncy ball is released from a certain height. on the first bounce, it travels 32cm. with each subsequent bounce, it travels 9/10 the distance of the previous bounce. what is the total distance that the ball has traveled when it completes its 25th bounce?

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?