Question 334692
4B + 3M = 145 cents
2B + 5M = 125 cents

This second equation tells you that buying twice as much will give you:
4B + 10M = 250 cents

So, now, compare the two equations:
4B + 3M = 145 cents
4B + 10M = 250 cents

Since both have the same number of books, the only difference is in the number of magazines:
7 extra magazines accounts for 105 cents (subtracting 10M - 3M, and 250 - 145).

So, magazines must cost 15cents, or $0.15 each.
And putting this value into one of the original equations:
4B + 3 * 15 = 145
4B = 100
B = 25 cents = $0.25

So, magazines cost $0.15, and books cost $0.25.