in 代數方程
1. Donna buys some $2 stamps and some $5 stamps.If she spends $54 altogether and gets 15 stamp, now how many $2 stamp does she buy?
2.A cash voucher,either $200 or $300,is given to eash of 45 staff members.If the total amount of thes vouchers given is $11800,find the nuber of staff members who receive a $200 voucher.
f.1 maths
2009-10-28 3:05 am
回答 (3)
2009-10-28 3:12 am
✔ 最佳答案
1. Let x be the numbers of $2 stamp she buys.So, (15 - x) is the number of $5 stamp she buys
Total value = $54
So, 2x + 5(15 - x) = 54
2x + 75 - 5x = 54
-3x + 75 = 54
-3x = 54 - 75
-3x = -21
x = 7
So, she buys 7 $2 stamp.
2. Let y be the numbers of staff who receive a $200 voucher,
so (45 - y) is the number of staff who receive a $300 voucher
Total value = $11 800
200y + 300(45 - y) = 11 800
2y + 135 - 3y = 118
-y = 118 - 135
-y = -17
y = 17
So, there are 17 staff who receive a $200 voucher.
參考: Physics king
2009-10-28 3:27 am
Let the number of stamps of $2 be X.
2X + 5(15-X)=54
2X+75-5X=54
-3X=-21
X=7
So, She buys 7 $2 stamps.
2. Let the number of staff members who receive $200 voucher be X.
200X+300(45-X)=11800
200X+13500-300X=11800
-100X=-1700
X=17
So, the number of staff members who receive$200 voucher is 17.
2X + 5(15-X)=54
2X+75-5X=54
-3X=-21
X=7
So, She buys 7 $2 stamps.
2. Let the number of staff members who receive $200 voucher be X.
200X+300(45-X)=11800
200X+13500-300X=11800
-100X=-1700
X=17
So, the number of staff members who receive$200 voucher is 17.
2009-10-28 3:16 am
1. Let the number of stamps of $2 be X.
2X + 5(15-X)=54
2X+75-5X=54
-3X=-21
X=7
So, She buys 7 $2 stamps.
2. Let the number of staff members who receive $200 voucher be X.
200X+300(45-X)=11800
200X+13500-300X=11800
-100X=-1700
X=17
So, the number of staff members who receive$200 voucher is 17.
2X + 5(15-X)=54
2X+75-5X=54
-3X=-21
X=7
So, She buys 7 $2 stamps.
2. Let the number of staff members who receive $200 voucher be X.
200X+300(45-X)=11800
200X+13500-300X=11800
-100X=-1700
X=17
So, the number of staff members who receive$200 voucher is 17.
收錄日期: 2021-04-19 20:15:09
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