1272: A worker reaches his factory 3 minutes late if his speed from his house to the factory is 5 km/hr. If he walks at a speed of 6 km/hr, then he reaches the factory 7 minutes early. The distance of the factory from his house is
(a) 4 km
(b) 5 km
(c) 6 km
(d) 7 km
1274: Write in chronological order"
(i) Man's landing on moon.
(ii) Discovery of radio activity.
(iii) First nuclear explosion.
(iv) Launching of first satellite by India.
(a) (iii), (ii), (iv), (i)
(b) (i), (ii), (iii), (iv)
(c) (iii), (i), (iv), (ii)
(d) (ii), (iii), (i), (iv)