Problem Solving

Hi All,

We're told that a plane contains R rows, each of which consists of D double seats and T triple seats. We're asked for the number of seats on the plane. This question can be solved by TESTing VALUES.

IF....
R=2, D=3 and T=4, then there are 2 rows with 3(2) + 4(3) = 6+12 = 18 seats in each row.
With 2 rows, that is 2(18) = 36 total seats

There's only one answer that matches...

Final Answer: C

GMAT assassins aren't born, they're made,
Rich

BTGmoderatorRO wrote:How many passengers can be seated on a plane with r rows, if each row consists of d double seats and t triple seats?

(A) rdt

(B) rd + rt

(C) 2dr + 3tr

(D) 3dr + 2tr

(E) rd + t

OA is c
What is wrong with option C and D here? I am confused.

d double seats will seat 2d passengers
t triple seats will seat 3t passengers
So, the total number of seats in ONE ROW = 2d + 3t

The plane has a total of r rows.
So, the TOTAL number of seats = r(2d + 3t)
Check the answer choices....not there (at least not in the above form)

Expand to get: 2dr + 3tr
Answer: C

Cheers,
Brent