A man ordered a length of rope by telephone from his nearest hardware shop. But when a worker in shop brought rope, he found that man on telephone had miswritten order by interchange feet and inches. As a result of this, length of rope received was only 30% of length he had ordered. The length of rope which man ordered was between :

Suppose the man ordered x feet y inches of the rope. Since x and y represent inches in the miswritten and actual order respectively, so each one of x and y is less than 12.
[ $$\because $$1 feet = 12 inches]
Actual order = x feet y inches = (12x + y) inches
Miswritten order = y feet x inches = (12y + x) inches
∴ (12y + x) = 30% of (12x + y) = $$\frac{3}{10}$$ (12x + y)
⇒ 10 (12y + x) = 3 (12x + y)
⇒ 26x = 117y
⇒ $$\frac{x}{y}$$ = $$\frac{117}{26}$$ = $$\frac{9}{2}$$
Since x < 12, y < 12, so x = 9, y = 2
Hence, the man ordered 9 feet 2 inches of rope.