In a bus, there were 3/4 as many adults as children. after 14 adults boarded the bus, the number of children was 2/5 of the number of adults. how many adults were there in the bus at first?

Question

Clay Dillon

Mathematics

29 December, 08:10

In a bus, there were 3/4 as many adults as children. after 14 adults boarded the bus, the number of children was 2/5 of the number of adults. how many adults were there in the bus at first?

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Answers (1)

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Elizabeth Price · Answer 1

There were 6 adults on the bus to start with.

We can set up a system of equations to solve this:

A = 3/4C

2/5 (A+14) = C

We will substitute the value for the first equation into the second equation to solve:

2/5 (3/4C+14) = C

Using the distributive property, we have:

2/5 (3/4C) + 2/5 (14) = C

6/20C + 28/5 = C

It's usually easier to not deal with fractions. Since th denominators of both fractions will go into 20, we will multiply everything in the equation by 20:

20 (6/20C) + 20 (28/5) = 20 (C)

6C + 560/5 = 20C

6C + 112 = 20C

Subtract 6C from both sides:

6C + 112 - 6C = 20C - 6C

112 = 14C

Divide both sides by 14:

112/14 = 14C/14

8 = C

Plugging this back into the first equation, we have:

A = 3/4 (8) = 24/4 = 6.