Question

At an amusement park you get five points for each bull’s eye you hit, but you loose 10 points for every miss. After 30 tries, Yolanda lost 90 points. How many bull’s eyes did she hit?

Answer 1

She hit 21 bull’s eyes.

Answer 2

Answer:

21

Step-by-step explanation:

14 bull's eyes (or hits) and 16 misses.  

The 14 hits earned her five points each, or a total of 70 points.  

The 16 misses cost ten points each, or a total of 160 points lost.  

14 + 16 = 30  

70 - 160 = -90  

SOLUTION:  

points = 5H - 10M = -90 where H = hits and M = misses  

tries = H + M = 30 therefore  

H = 30 - M  

and 5(30 - M) - 10M = -90  

150 - 5M -10M + 90 = 0  

240 -15M = 0  

15M = 240  

M =16  

H = (30 - M) = 16