Question 60

Ratio and proportion: 0.1:10::x:400 leads to x being 4.

To solve the proportion 0.1:10::x:400, we can set up the equation 0.1/10 = x/400. By cross-multiplying and simplifying, we find that x equals 4.

A) 5

This option is incorrect because substituting x with 5 in the proportion does not maintain the equality. If x were 5, the ratio would not be equivalent to 0.1:10 when compared to 5:400.

B) 4

This option is correct as substituting x with 4 maintains the equivalence of the ratios. The calculation shows that 0.1/10 equals 4/400, confirming that both sides of the proportion are equal.

C) 25

This option is incorrect since substituting x with 25 disrupts the ratio's equality. The ratio 0.1:10 does not equal 25:400, as verified through cross-multiplication.

D) 50

This option is also incorrect. If x were 50, the ratio would not hold, as shown by the calculations that would yield a different value when comparing the two sides of the ratio.

Conclusion

The answer 4 is definitively correct as it accurately satisfies the given proportion by maintaining equality between both sides. All other options fail to do so, demonstrating that they do not fulfill the requirements of the ratio presented in the question.