Chapter 2.5, Problem 20P

A county has two elementary schools, school A and school B. At school A, 30% of the children speak Spanish at home. At school B, 20% of the children speak Spanish at home. Use this information about the schools in all parts of this problem.

a. Tom says that 50% of the elementary school children in the county speak Spanish at home. Tom found 50% by adding 30% and 20%. Is Tom correct? Explain why or why not.

b. DeShun says that 25% of the elementary school children in the county speak Spanish at home. DeShun found 25% by averaging 30% and 20%.

i. If there are 400 children in school A and 100 children in school B, is DeShun correct that 25% of the elementary school children in the county speak Spanish at home? If not, what percent is it?

ii. If there are 100 children in school A and 400 children in school B, is DeShun correct that 25% of the elementary school children in the county speak Spanish at home? If not, what percent is it?

iii. Find circumstances under which DeShun is correct that 25% of the elementary school children in the county speak Spanish at home.