half hour trick. beware

Test Preparation SAT Preparation
1

<p>A merchant sells three types of colcks that chime as indicated by the check marks in the table above.What is the total number of chimes of the inventory of clocks in the 90-minutes period from 7:15 to 8:45?
答案为什么是149嘞？ The answer why is 149嘞? 怎么我算的是162？ How I have calculated that the 162?</p>

<p>i thought, half hour is every 30 minutes, so 7:30, 8:00 and 8:30 fall in this category but the ryt answer is 7:30 and 8:30 only</p>

<p>isnt it half hour is 30 minutes?</p>

2

<p>每“half hour” 是指 7:30， 8：30， 2：30， 11：30. 八点半， 九点半， etc etc.</p>

3

<p>8:00 is on the hour
7:30, 8:30 are on the half hour</p>

<p>the hours are 12:00, 1:00, 2:00, 3:00, 4:00, etc. (24 in a day)
an hour can be 12:30 - 1:30 (any)</p>

<p>a decade could be ANY 10 years (e.g., 1992-2002, 1993-2003)
the decade is specific (e.g., 1990-2000, 2000-2010)</p>