The price of commodity X increases by 40 paise every year, while the price of commodity Y increases by 15 paise every year. If in 1988, the price of commodity X was 4.20 and that of Y was 6.30, in which year will commodity X cost 40 paise more than commodity Y?
Options.
A) 1997	B) 1998	C) 1999	D) 2000	E) none of these

Rationale: suppose in ‘ n ’ years the price of comodity x will be more by 40 paise than that of commodity y . ∴ 420 + 40 n – 630 – 15 n = 40 or , 25 n – 210 = 40 or , 25 n = 250 or , n = 250 ⁄ 25 = 10 years . answer b
Answer: B