PrepLattice is an independent test-preparation service and is not affiliated with or endorsed by GMAC, the organization that administers the GMAT. GMAT and GMAT Focus are trademarks of GMAC, used here only to name the exam this question is designed to prepare you for.
A carrier audits 500 shipments. 70% arrive on time. Of the late shipments, 60% are late by under an hour. Of the shipments late by an hour or more, 25% are lost entirely. How many shipments are lost entirely?
Five fresh questions every day, your progress tracked, every miss explained. Free with an account.
Correct answer
A
Work level by level. Late shipments: 30% of 500 = 150. Of those, 60% are under an hour, so an hour or more is 40% of 150 = 60. Lost entirely: 25% of that 60 = 15. As an independent check, multiply the fractions in one chain: 0.30 × 0.40 × 0.25 × 500 = 0.03 × 500 = 15.
The key discipline is re-anchoring each 'of the ...' clause to the narrowed subset. Choice 37.5 applies 25% to all 150 late shipments, collapsing the hour-or-more narrowing. Choice 22.5 applies it to the wrong sub-group. Choices 60 and 90 stop at an intermediate count.
Pick the theme that suits how you work. You can change it anytime.