Data Sufficiency

lheiannie07 wrote:A bag contains a mixture of beans and pulses. To achieve 20 percent beans in the mixture, what percent of the mixture should be taken out and replaced with pulses?

(1) The mixture originally has 40 percent beans and 60 percent pulses.
(2) Total quantity of the mixture is 20 lb.

What's the best way to determine whether statement 1 is sufficient? Experts advice please

OA A

Statement 1: The mixture originally has 40 percent beans and 60 percent pulses.

Currently, we have 40% beans and 60% pulses.

We want to have 20% beans in the final mixture. Since the total quantity of the mixture after the replacement with the pulse is the same (= 100%), to get 20% beans in the final mixture, we must remove 40% - 20% = 20% points of beans from the mixture. This means that half (20/40 = 1/2) the quantity of beans to be removed and replaced with the pulse.

'Half' can be represented as 50% in percentage terms. Thus, 50% mixture to be removed and replaced with the same quantity of pulses. Sufficient.

Statement 2: Total quantity of the mixture is 20 lb.

Insufficient since we do not know the ratio of beans to pulses.

The correct answer: A

Hope this helps!

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