For the first;
For every four marbles, Izuku placed 2x more in the jar.
4x+24=84 4x=60 x=15 length =27 width = 15
A * b = 30
a - b = 1
a + b = 11
take ur last 2 equations, and add them
a - b = 1
a + b = 11
--------------add
2a = 12
a = 12/2
a = 6
now its just a matter of subbing
a + b = 11
6 + b = 11
b = 11 - 6
b = 5
so a = 6 and b = 5...whose product is 30, whose difference is 1, and whose sum is 11.
In order to solve this problem, we need to set up a proportion. I am setting the amount of calories in 10 ounces of grape juice equal to x.

We begin to solve this by cross multiplying.
8x = 1,100
To finish the problem, we divide both sides by 8.
x = 137.5, so the 10 ounce glass of grape juice will have 137.5 calories.