Let's begin by listing out the information given to us:
1/4 batch of cookies = 1/10 hour
x batches of cookies = 1 hour
To solve for the number of batches of cookies in one 1 hour, we will use simple proportion
x * 1/10 = 1/4 * 1
4x = 10
x = 10/4 = 2.5
Hence, 2½ batches of cookies are done in 1 hour