Question 28

X = 40

To find the value of X in the ratio 3:10 :: 12:X, one can set up a proportion. By cross-multiplying, we have 3 * X = 10 * 12, leading to X = 40.

A) X = 3.6

This option is incorrect because substituting X with 3.6 in the proportion does not satisfy the equality. If we calculate 3 / 10 and compare it with 12 / 3.6, the two ratios do not equate, confirming that 3.6 is not a valid solution.

B) X = 40

This option is correct. Substituting X with 40 gives us the equation 3 / 10 = 12 / 40. Simplifying 12 / 40 results in 3 / 10, thus maintaining the equality and confirming that X = 40 is indeed the right answer.

C) X = 0.27

This option is incorrect as substituting X with 0.27 does not maintain the ratio integrity. The calculated ratio 12 / 0.27 does not equal 3 / 10, thus showing that 0.27 cannot be the value for X.

D) X = 2.5

This option is also incorrect. If we substitute X with 2.5, the ratio 12 / 2.5 does not equal 3 / 10. This shows that 2.5 fails to satisfy the condition set by the proportion, proving it is not the correct answer.

Conclusion

The value of X = 40 is definitively correct as it maintains the equality of the ratios when substituted back into the proportion. All other options fail to satisfy the ratio requirement, confirming that they do not represent the correct solution to the problem. Thus, B is the only viable answer.