Question

Mary spent hour waiting for the school bus and to hour riding the bus to school. How much time did Mary spend in all?

Answer 1

7/10

1) Since May spent:

2/5 hour waiting

3/10 hour riding

2) We'll have to add them up. Since these fractions have different denominators (bottom number) let's calculate the LCM of 5 and 10:

So dividing them by prime numbers, the LCM is the product of 2 and 5 = 10.

So we can write:

`(2)/(5)+(3)/(10)=(10\colon5*2+10\colon10*3)/(10)=(4+3)/(10)=(7)/(10)`

3) Hence, Mary spent 7/10 of an hour in all.