*31. priya and ravish planned to participate in a cycle race to be organised for national integration. they decided
to practise on a circular path around a sports field. priya takes 18 minutes to complete one round, while rav-
ish takes 12 minutes for the same. suppose they both start at the same time and go in the same direction.
(a) after how many minutes will they meet again at the starting point?
(6) what is the value depicted by priya and ravish?

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.