Bunny27 wrote:alfretztay wrote:Daddy wrote:Hi,

Not so understand for

"boys: 2 x +18 Note: 90/10 x 2 = 18"

Thank.

As "the number of boys will be 10 x + [90]", after 80% boys left, we would have 20% of (10u + 90) = 2u + 18. Hence, "boys: 2 x + 18 Note: 90/10 x 2 = 18."

Bunny27

Post subject: P5 Ratio

Posted: 27 Jul 2014 21:03

OrangeBelt

Joined: 26 Jan 2011 21:18

Posts: 69

Hi,

Can someone help me on this problem sum?

1. At first, Maria had $243 and Huimei had $183. Later, eachof them bought a calculator and a dictionary. The dictionary cost twice as much as the calculator. Then the ratio of Maria's money to Huimei's money became 3:2.

a) How much money did Maria have left?

b) What was the cost of each dictionary?

Thank you...

Let the cost of a calculator be 1u.

Then, $243-3u->3p and

$183-3u->2p.

1p->$60

3p->$180[answer for a)].

$183-3u->$120

3u->$63

1u->$21

2u->$24[answer for b)].