a fast growing mushroom doubled in size every day. after 30 days it measured 6in. tall on which day did it measure 1 -1/2 in tall

Day 30: 6 inches

Day 29: 3 inches
Day 28: 1 1/2 inches

day 28

To determine on which day the fast-growing mushroom measured 1 1/2 inches tall, we can work backwards from the given information.

We know that the mushroom doubles in size every day. On the 30th day, it measured 6 inches, so on the 29th day, it would have measured half that size, which is 6 inches divided by 2, resulting in 3 inches.

Continuing this pattern, on the 28th day, it would have measured half of 3 inches, which is 1.5 inches.

Therefore, the mushroom would have measured 1 1/2 inches tall on the 28th day.