Using fraction, 10 workers is a whole number (1). Adding five more workers, the result will be [tex]1 \frac{1}{2} [/tex], as based from the original. The answer is 9.
Solution :
10 : 18
Adds 5 workers (Left part of the ratio)
(15 : 18)[tex] \neq [/tex](10 : 18)
([tex] 1\frac{1}{2} [/tex]) [tex] \neq [/tex](1)
15 is 150% of 10.
18 ÷ 2 = 9
Therefore, 15 workers can assemble 9 car engines in 9 days.