1963 TMTA High School Algebra I Contest Problem 24

Problem

When $5$ is subtracted from a certain number, $N,$ $\frac{1}{5}$ of the number remains. The equation which expresses this relationship is:

$\text{(A)} \quad N-5=\frac{1}{5} \quad \quad \text{(B)} \quad \frac{1}{5}N-5=0 \quad \text{(C)} \quad 5N+25=N$

$\text{(D)} \quad N-5=\frac{1}{5}N \quad \text{(E)} \quad 5N-25=1$

The left side of the equation is $N-5$ . "When 5 is subtracted from a certain number $N$ ..."

The right side of the equation is $\frac{1}{5}N.$ "1/5 of the number remains."

Put them together to get $\boxed{\text{(D)} \quad N-5=\frac{1}{5}N}.$

1963 TMTA High School Mathematics Contests (Problems)
Preceded by Problem 23	TMTA High School Mathematics Contest Past Problems/Solutions	Followed by Problem 25