Jun Wei has 12 more 10 cent coins than 20 cent coins. The total value of all his coins is $5.40. Find the total number of coins he has.
40
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And
The answer is 40
To solve this problem, we can set up a system of equations based on the given information.
Let's assume that Jun Wei has x number of 10 cent coins and y number of 20 cent coins.
According to the problem, Jun Wei has 12 more 10 cent coins than 20 cent coins. So, we can express this relationship as:
x = y + 12 ...(Equation 1)
The total value of all his coins is $5.40. Since each 10 cent coin is worth 10 cents and each 20 cent coin is worth 20 cents, we can write the total value equation as:
10x + 20y = 540 ...(Equation 2)
Now, we can solve this system of equations to find the values of x and y, which represent the number of 10 cent coins and 20 cent coins respectively.
From Equation 1, we can substitute the value of x in Equation 2:
10(y + 12) + 20y = 540
Simplifying this equation:
10y + 120 + 20y = 540
Combine like terms:
30y + 120 = 540
Subtract 120 from both sides:
30y = 420
Divide both sides by 30:
y = 14
Now substitute the value of y back into Equation 1 to solve for x:
x = 14 + 12
x = 26
Therefore, Jun Wei has 26 10 cent coins and 14 20 cent coins. To find the total number of coins he has, we add the number of 10 cent coins and 20 cent coins:
Total number of coins = 26 + 14 = 40
So, Jun Wei has a total of 40 coins.
More syllabus D questions
Not good solUtion
Let x = ten and y = 20 cent coins
x = y+12
.10x + .20y = 5.40
Substitute y+12 for x in the second equation and solve for y. Insert that value into the first equation to solve for x. Check by putting both values into the second equation.