A mechanical toy on a circular track goes forward 3 in. and then backward 2 in. How many moves does the toy take to complete on 15 in. revolution of the track?
it advances 1 in/move
after 12 moves it has advanced 12 inches.
On the 13th move it covers the last 3 inches to complete the lap.
To find out how many moves the toy takes to complete a 15 inch revolution of the track, we need to determine how many times the toy moves forward and backward in one revolution.
The toy goes forward 3 inches and then backward 2 inches in each move. This means that in each move, it takes a net forward movement of 3 - 2 = 1 inch.
To complete a 15 inch revolution, the toy needs to make 15 moves of 1 inch each. Therefore, the number of moves the toy takes to complete a 15 inch revolution is 15.
In general, if the toy goes forward x inches and then backward y inches in each move, the number of moves it takes to complete a revolution of the track is given by the formula:
Number of moves = Length of revolution / (x - y)
Applying this formula to the given scenario, we have:
Number of moves = 15 inches / (3 inches - 2 inches) = 15 inches / 1 inch = 15 moves.