2018 AMC 10A Problem 6

Question

Sangho uploaded a video to a website where viewers can vote that they like or dislike a video. Each video begins with a score of

0,

and the score increases by

1

for each like vote and decreases by

1

for each dislike vote.

At one point Sangho saw that his video had a score of

90,

and that

65\%

of the votes cast on his video were like votes. How many votes had been cast on Sangho’s video at that point?

200

300

400

500

600

Let

N

be the total number of votes

The score is likes minus dislikes

If

65\%

of votes were like votes, then

35\%

of votes are dislike votes. Then Sangho’s score is

65\% - 35\% = 30\%

the total number of votes.

We know that Sangho’s score is

90,

so the total number of votes is

90 \div 30\% = 300.

Thus, B is the correct answer.

Problem 6 in other years