If ratio of a to b is 2 to 5, of b to c is 1 to 4, find....

If the ratio of a to b is 2 to 5, and the ratio of b to c is 1 to 4, what is the ratio of a to c?

(a) 1:2
(b) 1:10
(c) 5:8
(d) 5:4
(e) 5:2

Those are the choices for the problem.
Can someone please explain to me how to solve this?

lp_144 said:

If the ratio of a to b is 2 to 5, and the ratio of b to c is 1 to 4, what is the ratio of a to c?

Click to expand...

The simplest method is probably to form comparables. You have a:b = 2:5 and b:c = 1:4. You need to find a:c, so it would be helpful if you could have a:b:c.

By what you would need to multiply b:c in order to have the b-value from b:c "match" the b-value from a:b? What then would be a:b:c? What then would be a:c?

Simplify, if possible. Then compare with the listed answers.

If you get stuck, or are unsure of your steps or answer-choice, kindly please reply with a clear listing of your work and reasoning. Thank you!

Eliz.

Thanks! I think I got it.

1) 2:5 1:4

2) 2:5 5:20

3) 2:5:20

4) 1:10

lp_144 said:

If the ratio of a to b is 2 to 5, and the ratio of b to c is 1 to 4, what is the ratio of a to c?

(a) 1:2
(b) 1:10
(c) 5:8
(d) 5:4
(e) 5:2

Those are the choices for the problem.
Can someone please explain to me how to solve this?

Click to expand...

These kinds of problems are generally given in SAT where you need to solve the problem fast!

Given:

\(\displaystyle \frac{a}{b}\, = \, \frac{2}{5}\)

\(\displaystyle \frac{b}{c}\, = \, \frac{1}{4}\)

what do you get when you multiply:

\(\displaystyle \frac{a}{b}\cdot\frac{b}{c}\)

Subhotosh Khan said:

These kinds of problems are generally given in SAT where you need to solve the problem fast!

Given:

\(\displaystyle \frac{a}{b}\, = \, \frac{2}{5}\)

\(\displaystyle \frac{b}{c}\, = \, \frac{1}{4}\)

what do you get when you multiply:

\(\displaystyle \frac{a}{b}\cdot\frac{b}{c}\)

Click to expand...

I got 1/10. This method is easier, thanks!