Converting each of the given fractions into decimal form, we get,5/6 = 0.838/15 = 0.532/3 = 0.663/4 = 0.754/5 = 0.86/7 = 0.85Clearly, 0.85 does not lie between 0.83 and 0.53Hence the required fraction is 6/7.
Let the length of lamppost = L mThen,first part = L/3and second part = (3/8) x L/3 = L/8 and third part = 6 m 50 cm = 6.50 mFirst part + second part + Third part = length of lamppost ⇒ L/3 + L/8 + 6.5 = L ⇒ L - L/3 - L/8 =6.5 ⇒ (24L - 8L - 3L)/24 = 6.5 ⇒ 13L/24 = 6.5 ∴ L = (65.x 24)/13 = 12 m