標題:
Help !!! 20 point F.1 maths
發問:
Can you help me to do the maths please ;) Donna buy some $2 stamps and some $5 stamps. If she spends $54 altogether and get 15 stamps and get 15 stamps, how many $2 stamps does she buy ? P.S. Please show the whole equation :)
It's pleased to solve your problem. Let $2 stamps be x and $5 stamps be y 2x+5y=54 x+y=15 Hence, x=15-y 2(15-y)+5y=54 30-2y+5y=54 3y=24 y=8 Hence, 8+x=15 x=7 Therefore, she has just bought 7 numbers of $2 stamps and 8 numbers of $5 stamps
其他解答:
Assume she bought a $2 and b $5 stamps. Equating money spent: a($2) + b($5) = $54 2a+5b = 54 (1) Equating stamps bought: a+b = 15 (2) (2): a = 15 - b (3) (3) into (1): 2(15-b) + 5b = 54 3b = 24 b = 8 a = 15 - b = 15 - 8 = 7 Therefore she bought 7 $2 stamps and 8 $5 stamps req. ans = 7.
Help !!! 20 point F.1 maths
發問:
Can you help me to do the maths please ;) Donna buy some $2 stamps and some $5 stamps. If she spends $54 altogether and get 15 stamps and get 15 stamps, how many $2 stamps does she buy ? P.S. Please show the whole equation :)
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最佳解答:It's pleased to solve your problem. Let $2 stamps be x and $5 stamps be y 2x+5y=54 x+y=15 Hence, x=15-y 2(15-y)+5y=54 30-2y+5y=54 3y=24 y=8 Hence, 8+x=15 x=7 Therefore, she has just bought 7 numbers of $2 stamps and 8 numbers of $5 stamps
其他解答:
Assume she bought a $2 and b $5 stamps. Equating money spent: a($2) + b($5) = $54 2a+5b = 54 (1) Equating stamps bought: a+b = 15 (2) (2): a = 15 - b (3) (3) into (1): 2(15-b) + 5b = 54 3b = 24 b = 8 a = 15 - b = 15 - 8 = 7 Therefore she bought 7 $2 stamps and 8 $5 stamps req. ans = 7.
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