boys/girls=3/4=x/(x+5)
x=15
girls=20
Ratio PS
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Source: Beat The GMAT — Problem Solving |
- rajeshsources
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- pradeepkaushal9518
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this u can solve by plug in method
choose the answer option
12 if 12 are girls than boys will be 9 as boys:girls = 3:4 but difference is not 5 hence not possible
15 then no of boys cant be solved so not possible
20 then boys will be 15 and the difference is 5 so correct
choose the answer option
12 if 12 are girls than boys will be 9 as boys:girls = 3:4 but difference is not 5 hence not possible
15 then no of boys cant be solved so not possible
20 then boys will be 15 and the difference is 5 so correct
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frank1
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oh i call it backward solving....seems like it is called plugin method as well
when you start backward solving
it is good to start from option C(not a rule but....)
here the answer was at E so 3 tests only
when you start backward solving
it is good to start from option C(not a rule but....)
here the answer was at E so 3 tests only












