A farmer grows watermelons and cantaloupes. Let X represent the weight of the watermelon, and let Y represent the weight of a cantaloupe. The mean of X is 12 pounds, and the mean of Y is 3 pounds. Which answer choice correctly calculates and interprets the mean of the sum, S = X + Y?

X+Y=S, Y is 3 pounds and X is 12 you add them both and get 15 pounds which is S

X+Y=S, Y is 3 pounds and X is 12 you add them both and get 15 pounds which is S

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.