pls help - maths( steps and answer).........thank you!!!!
1.) Two months ago, the total weight of Leo and Wilson was 130 kg. They went to a fitness centre together for physical training.
Now, the weight of Leo drops by 1/4 and the weight of Wilson drops by 2/7.
If Leo weight 5 kg less than Wilson at present,
what were their respective weight two months ago?
中一數求救-緊急
2014-11-02 9:48 pm
回答 (1)
2014-11-03 12:03 am
✔ 最佳答案
Let Leo's weight two months ago be n kg.Then, Wilson's weight two months ago was (130 - n) kg.
Now, Leo's weight is n (1 - 1/4) kg,
Wilson's weight is (130 - n) (1 - 2/7).
It is known that Leo weight 5 kg less than Wilson at present, that is,
n (1 - 1/4) = (130 - n) (1 - 2/7) - 5
n (3/4) = (130 - n) (5/7) - 5
[由於見到分母有 4, 也有 7, 考慮兩邊都乘 28]
(28) n (3/4) = (28) [ (130 - n) (5/7) - 5 ]
21n = (4)(130 - n)(5) - 140
21n = (20)(130 - n) - 140
21n = 2600 - 20n - 140
41n = 2460
n = 60
130 - n = 70
Therefore, Leo's weight two months ago was 60 kg, and Wilson's weight two months ago was 70 kg.
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