Question

Answer all question

1.There is a circular path around a sports field. Erica takes 18 minutes to drive one round of the field.
Harriet takes 12 minutes. Suppose they both start at the same point and at the same time and go in
the same direction, after how many minutes will they meet?

2. Round the following to four significant figures.
i. 0.00095897
ii. 24596
​

Answer 1

1. LCM of 18 & 12 = 36 minutes

2. 0.00095897

explanation.

2 18 2 12

____I______ ___l_________

3 9 2 6

____l_______. ___I_________

3 3 3 3

_____l________. ___l_________

l 1

18= 2×3×3 12=2×2×3

1 2 2 1

=1 × 3 =2 × 3

L.C.M= product of greatest power of each prime factor.

2 2

= 2 × 3

=4×9 = 36

hence, time taken by both to meet again

LCM of 18 & 12 =36 minutes