## 12. 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 coin Question 12. 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.​

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1 month 2021-08-21T22:36:55+00:00 1 Answer 0 views 0

He has 40 coins

Step-by-step explanation:

20 cent: x

10 cent: y

y: x + 12

10y + 20x = 5.40 dollars

10(x+12) + 20x = 5.40 X  100

10x + 120 +  20x = 540 cents

10x + 20x = -120 + 540

30x =  420

30x  = 420

30          30

x = 14

x + 12 = 26

26 + 14 = 40

Thus he has 40 total coins, comprising of 14 coins  20 cents and 26 coins of 10 cents.

Source: New Syllabus Mathematics 1,  7th edition