Arrange the given ratios in descending order:
a. 7 : 15
b. 15 : 23
c. 17 : 25
d. 21 : 39
Choose the correct answer from the options given below
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → c > b > d > a
A ratio \(p:q\) has the value \(\frac{p}{q}\), so the ratios are compared as fractions, here by their decimal values.
a. \(\displaystyle \frac{7}{15}\approx0.467\)
b. \(\displaystyle \frac{15}{23}\approx0.652\)
c. \(\displaystyle \frac{17}{25}=0.68\)
d. \(\displaystyle \frac{21}{39}\approx0.538\)
From the largest to the smallest: c (0.68), b (0.652), d (0.538), a (0.467).
Shortcut: Compare each fraction with \(\frac{1}{2}\) first.
Only \(\frac{7}{15}\) is less than \(\frac{1}{2}\) (7 is less than half of 15), so a comes last
Only Option (3) ends with a