## Question

primary 6 | Maths | Measurement

Anyone can contribute an answer, even non-tutors.

##### Cindy

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Date Posted: 1 year ago
Views: 64
Eric Nicholas K
1 year ago
R:J is 4:5

After J spent 7/10 of her money, she has \$120 less than R.

I see the numbers 5 and 10. We change 4:5 into 8:10 for easy computation.

At the start, R had 8 units and J had 10 units. After J spent 7 units (i.e. 7/10 of her money), she had 3 units of money left.

So in the end, R had 4 units and J has 3 units. Since J had \$120 less than R at this point, the extra 1 unit represents \$120.

Since R had 4 units at first, R must have had \$480 at first.
Cindy
1 year ago
May I know R should be 8u and J should be 3u right? Because we already convert es to 8u:10u.
Eric Nicholas K
1 year ago

Yes, you are right.

In view of this, the 5 units difference represents \$120. After calculation, you should get 1 unit as \$24 and 8 units as \$192 so R had \$192 at first.

We deal with the new ratios at this point as the ‘units’ are related to the new ratio, not old one.
Cindy
1 year ago
Thank you very much.