Re M07-04
[#permalink]
16 Sep 2014, 00:34
Official Solution:
At a dog competition, a dog is awarded 10 points for successfully completing three exercises: running through 4 pipes, making 10 jumps, and walking on 2 beams. If Roofy earns 9 points after missing one pipe but completing the rest of the exercises perfectly, and Ralph earns 7 points after missing one pipe and one beam but completing the rest of the exercises perfectly, how many points does Butch earn if he misses 4 jumps but completes the rest of the exercises perfectly?
A. 8.2
B. 8.4
C. 8.8
D. 9.0
E. 9.2
A dog is awarded 10 points for successfully completing three exercises: running through 4 pipes (p), making 10 jumps (j), and walking on 2 beams (b). The total points equation can be expressed as \(4p + 10j + 2b = 10\).
Roofy earns 9 points after missing one pipe, which means missing one pipe reduces the points by 1. So, \(p = 1\).
Ralph earns 7 points after missing one pipe and one beam, which means missing one pipe and one beam reduces the points by 3. Therefore, \(p + b = 3\). Since \(p = 1\), we have \(b = 2\).
Substituting these values into \(4p + 10j + 2b = 10\) gives \(4*1 + 10j + 2*2 = 10\), which simplifies to \(j = 0.2\). Therefore, if Butch misses 4 jumps but completes the rest of the exercises perfectly, he will earn \(10 - 4j =10 - 4*0.2 = 9.2\) points.
Answer: E