Given:
An aquamum contains dolphins, sharks, and whales. There are twice as many dolphins as whales and 8 fewer sharks than dolphins and whales combined.
Required:
If there are w whales, which of the following represents the number of sharks
Explanation:
The question asks for the correct expression of the number of sharks in terms of whales and dolphins . If w represents the number of whales , then the phrase " twice as many dolphins as whales " means that there are 2w dolphins . Therefore , " dolphins and whales combined " is 2w + w , or 3w . Because there are 8 fewer sharks than dolphins and whales combined , you need to subtract 8 from 3w.
you can also answer this question by using the Picking Numbers strategy . Pick a small , positive number , like 5 , for the number of whales . If there are 5 whales and " twice as many dolphins as whales , " then there must be 10 dolphins . Combine the number of whales and dolphins and subtract 8 from that sum to find the number of sharks : ( 5 + 10 ) -8 = 15-8 = 7 . Plug in w = 5 to determine which answer choice gives you a value of 7
Final answer:
B
