You will want to subtract the amount he ran on Monday from the amount on Tuesday. In order to subtract fractions, we must set them to the same denominator (bottom number). In order to do this, we must multiply 3/5 by 6/6 (the denominator on tuesday) which gets us 18/30. Then, for Tuesday, we must multiply 2/6 by 5/5 (the denominator on Monday) which is 10/30. Now, we can do Monday-Tuesday, 18/30-10/30 which gets us 8/30, if we simplify this, we get 4/15 :)
Step 1: Find out how many cm3 is filled in a minute. 750000/30 = 25000cm3 per minute Step 2: Find out how many minutes it takes to fill 1200000cm3. 1200000/25000 = 48 minutes
