using algebra to solve problems F1math

秋玲

2007-12-21 10:18 pm

要步驟

1. The different between two numbers is 15.the sum of the larger numberb is 15.the sum of the larger number and 8/5 of yhe smaller nuber is54.thind the larger number.

2. There are some chicken and rabbits in a cage .1/3 of the rabbits were born to have 3 legs .if the total number of headsis 35 and the total nuber of legs is 90,find the number of

a)chicken

b)rabbits with 4 legs

回答 (1)

LeungHei Noh

2007-12-22 11:52 pm

✔ 最佳答案

1. Let the larger number be X.
X+8/5(X-15)=54
X+8X/5=78
13X=390
X=30
the larger number is 30

2. There are some chicken and rabbits in a cage .1/3 of the rabbits were born to have 3 legs .if the total number of headsis 35 and the total nuber of legs is 90,find the number of

a)Let the number of chicken be X and the number of rabbits be Y
X+Y=35---1
2X+11Y/3=90---2

2*3: 6X+11Y=270---3

1*11-3: 5X=115
X=23

the number of chicken is 23

b)Since X=23
23+Y=35
Y=12
the number of rabbits with 4 legs=2Y/3
=8

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