The question is asking us to calculate how many envelopes are there in 7 packages if there are 75 in a package. For example: in 1 package there are 75 envelopes. In 2 packages there are 7 * 2 = 150 envelopes. In general, formula is : 75 * n, where n is the number of packages. Therefore, we will multiply 75 by 7. 75 * 7 = 525. Answer: B ) 525 envelopes.