GMAT Quantitative practice questions

A mobile app developer tracks installs from two channels: organic and paid. Last month, organic installs accounted for 0.60 of total installs, while paid installs accounted for 0.40 of total installs. If the total number of installs last month was between 100 and 150, what are the minimum and maximum possible number of organic installs?

A logistics company has two shipping routes: Route A and Route B. Packages shipped via Route A take 4 days longer than those shipped via Route B. When 3 packages are sent via Route A and 2 packages via Route B, the total shipping time for all packages is 22 days. Determine the following:

A logistics company offers two shipping methods: Standard $S$ and Express $E$. Express shipments cost 40% more per package than Standard but guarantee delivery in half the time. For a bulk order, the company charges $2,400 total when 100 packages are sent via Standard and 50 via Express. Separately, when 60 packages are shipped via Standard only, the total delivery time is 36 hours. Determine the following:

A weather station recorded monthly rainfall for two consecutive years. In Year A, the median monthly rainfall was 20 mm, and the range (difference between highest and lowest monthly rainfall) was 30 mm. In Year B, the mean monthly rainfall was 10% higher than in Year A, and the range was 25% narrower than in Year A. The total rainfall for both years combined was 600 mm. Determine the following:

A university tracks enrollment in its introductory Biology and Chemistry courses. In the fall term, Biology had 30 students and Chemistry had 20 students. In the spring term, Biology enrollment increased by 10 students while Chemistry enrollment decreased by 10 students. Select the difference in enrollment between Biology and Chemistry for the fall term and for the spring term.