A. 11

B. 13

C. 15

D. 17

E. 19

The OA is B

**Source: GMAT Paper Tests**

00:00

**A**

**B**

**C**

**D**

**E**

An optometrist charges $150 per pair for soft contact lenses and $85 per pair for hard contact lenses. Last week she sold 5 more pairs of soft lenses than hard lenses. If her total sales for pairs of contact lenses last week were $1,690, what was the total number of pairs of contact lenses that she sold?

A. 11

B. 13

C. 15

D. 17

E. 19

The OA is B

**Source: GMAT Paper Tests**

A. 11

B. 13

C. 15

D. 17

E. 19

The OA is B

- GMATGuruNY
- GMAT Instructor
**Posts:**15495**Joined:**25 May 2010**Location:**New York, NY**Thanked**: 13060 times**Followed by:**1879 members**GMAT Score:**790

Since $150 soft lenses and $85 hard lenses yield $1690 in revenue, we get:swerve wrote:An optometrist charges $150 per pair for soft contact lenses and $85 per pair for hard contact lenses. Last week she sold 5 more pairs of soft lenses than hard lenses. If her total sales for pairs of contact lenses last week were $1,690, what was the total number of pairs of contact lenses that she sold?

A. 11

B. 13

C. 15

D. 17

E. 19

150S + 85H = 1690

30S + 17H = 238

The sum on the left side must yield a units digit of 8.

Since 17*4 = 68, it is likely that H=4:

30S + 17*4 = 338

30S + 68 = 238

30S = 170

S=9

S=9 and H=4 satisfy the condition that the optometrist sells 5 more pairs of soft lenses than hard lenses.

Thus, the total number of pairs = 9+4 = 13.

The correct answer is B.

Mitch Hunt

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