The table above shows the quantities and prices per pound of three types of nuts that are combined to make a nut mixture

[BTGmoderatorDC]

The table above shows the quantities and prices per pound of three types of nuts that are combined to make a nut mixture. The mixture contains twice as many pounds of cashews as pounds of almonds, and 3 times as many pounds of walnuts as pounds of almonds. What is the cost of the mixture, in dollars, expressed in terms of a?

A) 4a
B) 6a
C) 13.5a
D) 20.5a
E) 24.5a


OA E

Source: GMAT Prep

[swerve]

The table above shows the quantities and prices per pound of three types of nuts that are combined to make a nut mixture. The mixture contains twice as many pounds of cashews as pounds of almonds, and 3 times as many pounds of walnuts as pounds of almonds. What is the cost of the mixture, in dollars, expressed in terms of a?

A) 4a
B) 6a
C) 13.5a
D) 20.5a
E) 24.5a


OA E

Source: GMAT Prep

The ratio:

cashews: almonds: walnuts \(= 2 : 1 : 3\)

\(2a: 1a: 3a\)

Although we know the ratio of the quantity, simply adding up the ratio is not correct. This would give us \(6a,\) which is a trap answer. We need to take into consideration how each quantity is weighted:

\(2a \cdot 3.5 = 7a\)
\(a \cdot 4 = 4a\)
\(3a \cdot 4.5 = 13.5a\)
total \(= 24.5a\)

Therefore, E