Answer:
x = 3
Step-by-step explanation:
The midsegment is half the sum of the parallel bases, that is
(3x + 3 + 4x + 2) = 13
(7x + 5) = 13 ( multiply both sides by 2 )
7x + 5 = 26 ( subtract 5 from both sides )
7x = 21 ( divide both sides by 7 )
x = 3
Let his total money be x.
He spent (3/7)*x of his money.
He gave 1/4(x-3/7x) to his sister.
which is : (1/4)*(4/7)*x = (1/7)*x
Now,
How much money he have in the beginning =
(3/7)*x+(1/7)*x+120=x
(4/7)*x+120=x
120=x-(4/7)*x
120=(3/7)*x
x=120*7/3 [cross multiplication]
x=280.
So, Alex had $280 in the beginning.
We can use the distance formula to find the distance between these points.
Distance formula: 
√(-5 - 6)² + (-3 - (-3))²
√121 = 11
The difference between the points is 11.
0 if you add the thickness to the underside of the tank