PDA

View Full Version : sat math problem average

elizabeth
10-19-2013, 07:06 PM
25% of the officers in a camp are senior officers and the remaining are junior officers. The monthly wage of each senior officer is $4,500 and the monthly wage of each junior officer is$3,500. What is the average monthly wage of all officers in the camp?

(A) \$3,550 (B) \$3,650

(C) \$3,750 (D) \$3,850

Thanks!

10-19-2013, 07:10 PM
Let x be the total number of officers in this camp. The number of senior officers would be 0.25x and the number of junior officers would be 0.75x.

The total monthly wages of all senior officers would be 0.25x \cdot \$4,500=\$1,125x

Similar, the total monthly wages of all junior officers would be 0.75x \cdot \$3,500=\$2,625x

Hence, the total monthly wages of all officers would be \$1,125x +\$2,625x=\$3,750x Therefore, the average monthly wage of all officers would be \frac{\$3,750x }{x}=\\$3,750

Therefore the correct answer is (C).

elizabeth
10-19-2013, 07:11 PM
thank you!