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A ferry can carry 20 bus or 32 cars. if the ferry is loaded with 15 bus, then how many cars would be in the ferry ?

Russel Ahmed
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  • I assume that the ferry is fully loaded? –  May 16 '17 at 08:24
  • Note that this says that a car takes $\frac{20}{32}$ the space of a bus. So if it is loaded with 15 buses, then the space remaining is 5 buses, which is enough for $\frac{32}{20} \times 5 = 8$ cars. – Osama Ghani May 16 '17 at 08:24
  • If it has $15$ buses, then it's at $75$% capacity. So $25$% of its space is left, how many cars can it hold? – florence May 16 '17 at 08:25
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    This question is quite ambuguous. First of all do you consider a bus a special case of a car? Also note that it's normally not as easy as a bus takes $x$ times the space a car does. For example if there is no buses on the ferry you might be able to use an additional deck for cars. Also the spaces for some busses would only accomodate one car and spaces for other busses would be able to accomodate two or more cars. – skyking May 16 '17 at 08:29

1 Answers1

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Let $S$ be the total "space" or "max weight" the ferry has/can carry.

We know that $20b = S$ and $32c = S$ where $b,c$ are respectively the size/the weight of 1 bus or 1 car.

We now want to solve $15b + xc = S$ for $x$ the number of cars. $$ 15b + xc = S = 32c \\ x = 32-15\frac{b}{c} $$ Also $\frac{20b}{32c} = S/S = 1 \implies b/c = 32/20$.

I let you put the result together.

Zubzub
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