ruirrrr
请教大家一个小学数学应用题
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2024-08-22 17:49:07
ChatGPT says:
Let's break down the problem step by step to find out how many coins the boy has left.
Step 1: Define Variables
Let:
- ddd = the original number of dimes.
- nnn = the original number of nickels.
According to the problem:
- The boy has 43 more nickels than dimes, so n=d+43n = d + 43n=d+43.
- After spending 17 dimes, the boy has twice as many nickels as dimes.
Step 2: Set Up the Equation
After spending 17 dimes, the number of dimes left is d−17d - 17d−17. According to the problem, the number of nickels left is still nnn, and this is twice the number of dimes left:
n=2(d−17)n = 2(d - 17)n=2(d−17)
Step 3: Substitute the First Equation into the Second
We know that n=d+43n = d + 43n=d+43, so we substitute this into the second equation:
d+43=2(d−17)d + 43 = 2(d - 17)d+43=2(d−17)
Step 4: Solve for ddd
Expand and solve the equation:
d+43=2d−34d + 43 = 2d - 34d+43=2d−34
Subtract ddd from both sides:
43=d−3443 = d - 3443=d−34
Add 34 to both sides:
d=77d = 77d=77
So, the boy originally had 77 dimes.
Step 5: Find the Number of Nickels
Using the equation n=d+43n = d + 43n=d+43:
n=77+43=120n = 77 + 43 = 120n=77+43=120
So, the boy originally had 120 nickels.
Step 6: Calculate the Number of Coins Left
After spending 17 dimes, the boy has:
77−17=60 dimes left77 - 17 = 60 \text{ dimes left}77−17=60 dimes left
He still has 120 nickels.
Step 7: Total Number of Coins Left
The total number of coins left is:
60 dimes+120 nickels=180 coins60 \text{ dimes} + 120 \text{ nickels} = 180 \text{ coins}60 dimes+120 nickels=180 coins
So, the boy has 180 coins left.
到底了
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