Answer:
45
Step-by-step explanation:
The other answers are right but in case you’re confused why, let’s try to do it slowly.
First think, if you say “3/4 of something”, what does that mean? In elementary school, the kids are asked to visualise a cake and that’s as good a way to think about this as any. 3/4 of a cake means you take a cake, divide it equally into four parts, and then take three of those, remember?
Now instead of a cake, we have 5/8 of a cake. But the logic stays exactly the same. We start with 5/8 cake and divide it into four equal parts. To do so easily, first cut all five parts into four. We now have 20/32 of a cake. Now we can easily divide by 4, to get 5/32. And finally we take three of those, so we get 15/32.
Done!
Once you’ve internalised this logic, you can start to remember the rule:
Rule 1: abab “of” cdcd means ab⋅cdab⋅cd .
Rule 2: to multiply fractions, you can multiply numerator and denominator separately: ab⋅cd=acbdab⋅cd=acbd .
A couple other useful rules that are very similar are:
Rule 3 (dividing by fractions means multiplying by its reciprocal): ab/cd=ab⋅dcab/cd=ab⋅dc .
Rule 4 (percentages): n%n% just means n100n100 , so 30%30% of 150150 means 3010030100 of 150150 , and by the first two rules, that is the same as 30⋅150100=4530⋅150100=45 .
