Question

John was working at the registration desk of a conference that was scheduled to begin at 8:00 P.M. At 7:30, he texted the conference manager to report that only 20% of the registrants had signed in so far. At 7:45, he sent a second text stating that in the past 15 minutes, 90 additional people had signed in and that now 65% of the participants had arrived. Which of the following is closest to the total number of people who had registered for the conference?

(A) 140
(B) 200
(C) 250
(D) 450​

Answer 1

Hi Mehak!

Expert-Verified Answer

Answer:

Let's call the total number of people who had registered for the conference "x".

At 7:30, 20% of the registrants had signed in, so 0.20x people had arrived.

At 7:45, 65% of the participants had arrived, so 0.65x people had arrived.

The number of people who had arrived in the past 15 minutes was 90, so 0.65x - 0.20x = 90.

Solving for x:

0.45x = 90

x = 200

The answer closest to the total number of people who had registered for the conference is 200.

So, the answer is (B) 200.