Posted by **Da S** on Thursday, February 2, 2012 at 9:00am.

Mr Lim put some red pens and blue pens into a box.The ratio of the number of red pens to the number of blue pens was 3:4.

He added 20 red pens into the box and the ratio became 2:1.

a. were there more red pens or blue pens in the box at the end?

b. how many red pens were there in the end?

c. how many blue pens were there?

- math,(fraction) -
**Steve**, Thursday, February 2, 2012 at 10:50am
well, since the ratio r:b = 2:1 I'd say there were more r's...

(r+20)/b = 2/1

r/b = 3/4

so, b = 4/3 r

(r+20)/(4/3 r) = 2

r+20 = 8/3 r

5/3 r = 20

r = 12

so, there were 32 reds at the end

there were 4/3*12 = 16 blue pens. Note that 16 = 32/2 as well.

- math,(fraction) -
**Anonymous**, Monday, February 15, 2016 at 4:39am
I don't know my mom

## Answer This Question

## Related Questions

- Maths - A shopkeeper buys a number of blue pens and red pens. He pack 3 blue ...
- pre algebra - A college bookstore ordered 6 boxes of red pens. The store sold 32...
- Math - Bella keeps a supply of red, blue, and black pens in a drawer. The drawer...
- math - Bella keeps a supply of red, blue, and black pens in a drawer. The drawer...
- math - Bella keeps a supply of red, blue, and black pens in a drawer. The drawer...
- math - A college bookstore ordered six boxes of red pens. The store sold 32 red ...
- maths - Bella keeps a supply of red, blue, and black pens in a drawer. The ...
- algebra - A college bookstore ordered six boxes of red pens. The store sold 37 ...
- math - A box contains 4 red pens, 5 blue pens, and 9 green pens. Two pens are ...
- MATH HELP - There are 20 red and blue pens in abox. There are 3times as many ...

More Related Questions