(A) 120 stamps are divided among Mary, Peter and Betty . If Peter gets haif as many stamps as Mary,andBetty gets three times as many as peter,how many does each get?
(B) Steven's mother gave him $250. After buying some fish, which totally cost$45, he bought some tortoises at $16 each.If hehad $45 left, how many tortoises did he buy?
*(please use EQUATIONS)
please teach me some mathematics
2007-09-02 6:36 am
回答 (3)
2007-09-02 6:53 am
✔ 最佳答案
Let M be MaryP be Peter
B be Betty
2M=P
3B=P
M+B+P=120
M+B+2M=120 (2M=P)
M+3B+2M=120X3
M+2M+2M=360
5M=360
M=360/5
M=72
Mary has 72 stamps
P=2M => 72/2=36 Peter has 36 stamps
3B=P => 36/3=12 Betty has 12 stamps
72+36+12=120 stamps
(B)
Let T be tortoises
250-45-16T=45
250-45-45=16T
160=16T
16T=160
T=160/16
T=10
Steven bought 10 tortoises
2007-09-02 7:04 am
(A) Let Peter gets Y stamps, then Mary gets 2Y, and Betty gets 3Y;
Y+2Y+3Y=120
6Y=120
Then, Y=20
Therefore, Peter gets 20 stamps. Mary gets 40 stamps and Betty gets 60 stamps.
(B) Let T be the number of tortoises Steven bought;
$ (250-45-16T) = $45
16T=250-45-45
Then T=10
Y+2Y+3Y=120
6Y=120
Then, Y=20
Therefore, Peter gets 20 stamps. Mary gets 40 stamps and Betty gets 60 stamps.
(B) Let T be the number of tortoises Steven bought;
$ (250-45-16T) = $45
16T=250-45-45
Then T=10
2007-09-02 6:53 am
(a)當mary有 x 個郵票 ,咁peter有mary既一半= 1/2x ,betty有peter既3倍=3/2 x
佢地既郵票total有120,咁
x + 1/2x + 3/2 x =120
3x = 120
x = 40
so mary有40個郵票,peter有20個,betty有60個
(b)Let the number of tortoises steven bought be y,
250-45-16y=45
250-16y=90
-16y=-160
y=10
so steven had bought 10 tortoises
佢地既郵票total有120,咁
x + 1/2x + 3/2 x =120
3x = 120
x = 40
so mary有40個郵票,peter有20個,betty有60個
(b)Let the number of tortoises steven bought be y,
250-45-16y=45
250-16y=90
-16y=-160
y=10
so steven had bought 10 tortoises
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