Target Test Prep Sample GRE Multiple Answer Problem
In a fishing box with red, blue, and green worms, the ratio of red worms to blue worms is 5 to 6. The ratio of red worms to green worms is 4 to 3. How many blue worms could be in the box?
Indicate all such answers.
6
12
24
36
48
64
72
Solution:
We can let R = the number of red worms, B = the number of blue worms, and G = the number of green worms.
We know that the ratio of R to B is 5: 6 and that R to G is 4: 3.
The ratios do not share the same numbers, but they share a common variable, R. Because R is present in both ratios, we can find the LCM of the given values of R. In the first ratio, R = 5, but in the second ratio, R = 4. The LCM of 5 and 4 is 20. Multiplying the first ratio by 4 and the second ratio by 5 yields
R:B = 20:24 R:G = 20:15
Finally, we can put together the multi-part ratio, which is R : B : G = 20 : 24 : 15
We know that the number of blue worms must be a multiple of 24.
Thus the correct answer consists of Choices C (24), E (48), and G (72).
24
/48
/72
