Algebra Word Problems Help?

Question

I can't solve some word problems.

Find four consecutive integers such that the sum of the two greatest subtracter from twice the sum of the two least is 15.

and

The atomic numbers of radium, thorium, and uranium are consecutive even integer in increasing order. If three times the atomic number of radium is 82 more than the sum of the atomic numbers of thorium and uranium, what are the atomic numbers of these three elements?

Please help.

Answer 1

a) Let the consecutive integers be a, a+1, a+2, a+3

2[a+(a+1)] - [(a+2)+(a+3)] = 15
(4a+2) - (2a+5) = 15
2a - 3 = 15
a = 9

The integers are 9, 10, 11, 12.

b) Let the atomic numbers of radium, thorium, and uranium be b, b+2, b+4 respectively.

3b - [(b+2)+(b+4)] = 82
b - 6 = 82
b = 88

Radium = 88
Thorium = 90
Uranium = 92

Answer 2

2(n + n + 1) - (n + 2 + n + 3) = 15
4n + 2 - 2n - 5 = 15
2n = 18
n = 9
9, 10, 11, 12

3r = r + 2 + r + 4 + 82
r = 88
t = 90
u = 92