Test 4 Section 6 - #17 (page 598)

This is a weird question, but you just need to carefully follow the rules. Just work through the weird wording. When it says "chimes n times on the n th hour" that means like "2 times on the 2nd hour" or "10 times on the 10th hour". So from 7:15-8:45, the only hour we hit is 8:00, so the clocks will chime 8 times. Since there are 10 clocks of Type A, that's 80 chimes (8 chimes for each of the 10 clocks), and 5 clocks of Type B, that's 40 chimes (8 chimes for each of the 5 clocks).

Next column: "chimes once on the hour" means it'll chime once at 8:00. There are 3 clocks of Type C, so that's 3 chimes.

For the third column ("chimes once on the half hour"), we're hitting 2 half-hours: 7:30 and 8:30, so each will chime twice total. There are 10 Type A's (so that's 20 chimes) and 3 Type C's (so that's 6). Add 'em up: 80+40+3+20+6 = 149.