Answer is 2:1
This is the same as saying "2 to 1"
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Explanation:
m = number of pennies or dimes = 40+20 = 60
n = number of other coins = 18+12 = 30
The ratio m:n represents the odds in favor of getting a penny or a dime. We list the number of things we want first, followed by a colon, then the other value is everything we don't want. The ratio m:n updates to 60:30 which simplifies to 2:1. We have 2 to 1 odds in favor of getting the coin we want (a penny or a dime).
If your teacher was asking "odds against of getting a penny or dime", then we'd flip the ratio to 1:2 which is read out as "1 to 2".
