Question

2. To break the school's record, the boys' time had to be faster than 2,2 1 / 2minutes. Estimate to decide if the boys broke the record. If so, howmuch faster were they? If not, how much slower were they? I only need question 2 answered

Answer 1

2) We would add the times of each boy. We have

2/3 + 11/12 + 5/6 + 7/12

The lowest common multiple of the denominator is 12. We would divide each denominator by 12 and multiply the numerator by the result. It becomes

(2*4 + 11*1 + 5*2 + 7*1)/12

= (8 + 11 + 10 + 7)/12

= 36/12

= 3 minutes

Since 3 is greater than 2 7/12, it means that the boys broke the record. The difference between the times is

3 - 2 7/12

Changeing 2 7/12 to improper fraction, it becomes 31/12

Difference = 3 - 31/12 = (3 * 12 - 31)/12 = (36 - 31)/12

Difference = 5/12

The boys were faster with 5/12 minute