Problem Solving

BTGModeratorVI wrote: ↑

Sat Aug 08, 2020 7:07 am

A car dealer sold x used cars and y new cars during May. If the number of used cars sold was 10 greater than the number of new cars sold. Which of the following expresses this relationship ?

(A) x > 10y
(B) x > y + 10
(C) x > y – 10
(D) x = y + 10
(E) x = y – 10

Answer: D
Source: Official guide

The most common INCORRECT answer is E.

Here's one way to avoid this:
Given: x used cars and y new cars
Number of used cars (x) sold was 10 greater than the number of new cars (y) sold
So, x is 10 greater than y
To show their relative sizes let's write x LARGER than y to get: x and y

Our goal is to create an EQUATION. So, how do we make these two values EQUAL?
Well, we need to make the smaller value (y) bigger. 10 bigger to be exact.

So, we get x = y + 10
Answer: D

Cheers,
Brent

BTGModeratorVI wrote: ↑

Sat Aug 08, 2020 7:07 am

A car dealer sold x used cars and y new cars during May. If the number of used cars sold was 10 greater than the number of new cars sold. Which of the following expresses this relationship ?

(A) x > 10y
(B) x > y + 10
(C) x > y – 10
(D) x = y + 10
(E) x = y – 10

Answer: D
Source: Official guide

Solution:

Since the number of used cars sold was 10 greater than the number of new cars sold, we need to add 10 to the number of new cars sold to equal the number of used cars sold.

We can create the expression:

x = 10 + y

Answer: D