Answer:
34
Step-by-step explanation:
Marcy got 15% of the 40 wrong
.15 *40
6
If she got 6 wrong, then she got the rest right
40-6 = 34
She got 34 right
Answer:
D
Step-by-step explanation:
You are going to roll two dice.
If you roll one die, then there are 6 possible outcomes: 
If you roll two dice, then there are
possible outcomes:

Here the first number is the number rolled on the first die, the second number is the number rolled on the second die.
Answer:
There are 20 boys
Step-by-step explanation:
Answer:
y = -0.07x2 + 3.07x
Step-by-step explanation:
For each plant we add, there is a decrease of 70 grams for all plants from the inicial value of 3 kg of beans.
So, for 2 plants, we have (3 - 0.07) * 2
For 3 plants, we have (3 - 2*0.07) * 3
For x plants, we have (3 - (x-1)*0.07) * x
So we can model the final result of the amount of beans 'y' with the equation:
y = (3 - (x-1)*0.07) * x
y = (3 - 0.07x + 0.07) * x
y = (3.07 - 0.07x) * x
y = -0.07x2 + 3.07x
(In this equation we have a = -0.07, b = 3.07 and c = 0)