GMAC practice test - stumped

[Striver]

GMAC PRACTICE TEST

Shipment Number Defective Total Chips
S1 2 5000
S2 5 12,000
S3 6 18,000
S4 4 16,000

A computer chip manufacturer expects the ratio of the number of defective chips to the total number of chips in all future shipments to equal the corresponding ratio for shipments in S1, S2, S3, and S4 combined, as shown in the table above. What is the expected number of defective chips in a shipment of 60,000 chips?

A) 14
B) 20
C) 22
D) 24
E) 25

[Anurag@Gurome]

GMAC PRACTICE TEST

Shipment Number Defective Total Chips
S1 2 5000
S2 5 12,000
S3 6 18,000
S4 4 16,000

A computer chip manufacturer expects the ratio of the number of defective chips to the total number of chips in all future shipments to equal the corresponding ratio for shipments in S1, S2, S3, and S4 combined, as shown in the table above. What is the expected number of defective chips in a shipment of 60,000 chips?

A) 14
B) 20
C) 22
D) 24
E) 25

Total no. of shipments = 5000 + 12000 + 18000 + 16000 = 51000
Total no. of defective chips = 2 + 5 + 6 + 4 = 17
Let x be the expected number of defective chips in a shipment of 60000 chips.
Then 17:51000 = x:60000
x = 20

The correct answer is B.