Dr. Tim recorded an unladen European swallow flapping it wings at a constant rate of 50 wing beats each 30 seconds how many times will the swallow beat its wings in 4 minutes

400 wing beats

Step-by-step explanation:

Find out the number of 30 second periods in 4 minutes.

If there are two 30 second periods in 1 minute, 4 minutes will have:

= 2 * 4

= 8

The swallow flaps its wings at 50 wing beats per 30 seconds. There are eight 30 seconds periods in 4 minutes .

= 50 * 8

= 400 wing beats

whatever you can spend with $11.53 or under.

step-by-step explanation:

20 - 8.47 = 11.53. take away the money he used for lunch from the starting amount of 20.