1963 TMTA High School Algebra I Contest Problem 37

Problem

A man has $$3000$ invested at $x\%$ and $$2000$ at $(x+1)\%.$ The annual interest on the investments totals $$220.$ Find the $x$ rate.

$\text{(A)} \quad 2\% \quad \text{(B)} \quad 4\% \quad \text{(C)} \quad 3\frac{1}{2}\% \quad \text{(D)} \quad 5\% \quad \text{(E) NOTA}$

Plug in each of the answer choices. We see that the right answer is $\boxed{\text{(B)}}.$ $100(4/3000)+(5/2000)=220$

1963 TMTA High School Mathematics Contests (Problems)
Preceded by Problem 36	TMTA High School Mathematics Contest Past Problems/Solutions	Followed by Problem 38