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kevincan
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A city currently has 75,000 new cases of measles reported ea Updated on: 11 Mar 2026, 14:21
Originally posted by kevincan on 11 Mar 2026, 12:54.
Last edited by kevincan on 11 Mar 2026, 14:21, edited 1 time in total.
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55% (hard)

Question Stats:

66% (02:28) correct 34% (02:12) wrong based on 59 sessions

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A city currently has 75,000 new cases of measles reported each day. Beginning tomorrow (Tuesday), the number of new cases reported each day will decrease by 50 percent each day. If this rate continues, on which day of the week will the number of new cases reported in a day first fall below 100?

A. Wednesday
B. Thursday
C. Friday
D. Saturday
E. Sunday
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B
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A city currently has 75,000 new cases of measles reported ea 11 Mar 2026, 13:05
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The answer would be Thursday simply by 75000/2^10 would be first instance of less than 100. So if first day is Tuesday
Eighth day will again be Tuesday and 10th Day would be Thursday
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A city currently has 75,000 new cases of measles reported ea 11 Mar 2026, 14:27
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Was this your first post ? Thanks for pointing out that the official answer needed to be changed!
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A city currently has 75,000 new cases of measles reported ea 11 Mar 2026, 17:13
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75,000(1/2)^x = 100
(1/2)^x = 1/750
2^x = 750
2^9 = 512 and 2^10 = 1024, so we know the reported number of cases will first fall below 100 on the 10th day.

If that first Tuesday is represented by 2^1, the next Tuesday will be 2^(1+7), and so 2^10 will be two days after this, or Thursday.

Answer choice B
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A city currently has 75,000 new cases of measles reported ea 12 Mar 2026, 04:24
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kevincan
A city currently has 75,000 new cases of measles reported each day. Beginning tomorrow (Tuesday), the number of new cases reported each day will decrease by 50 percent each day. If this rate continues, on which day of the week will the number of new cases reported in a day first fall below 100?

A. Wednesday
B. Thursday
C. Friday
D. Saturday
E. Sunday
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The number of cases on Monday = 75000.

From Tuesday, the new cases will decrease by 50% per day.

75000 (1/2)^n < 100

(1/2)^n < (1/750)

750 < 2^n

2^9 = 512. Then, 2^10 = 1024.

n = 10.

Monday to Monday is 1 week = 7 days.

We are left with three days. 3 days after Monday = Thursday.

Option B
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