A. 16 : 9
B. 9 : 16
C. 4 : 3
D. 3 : 4
There are 8436 steel balls, each with a radius of 1 centimeter, stacked in a pile, with 1 ball on top, 3 balls in the second layer, 6 in the third layer, 10 in the fourth, and so on. The number of horizontal layers in the pile is
The length of a ladder is exactly equal to the height of the wall it is resting against. Iflower end of the ladder is kept on a stool of height 3 m and the stool is kept 9 m awayfrom the wall, the upper end of the ladder coincides with the top of the wall. Then,the height of the wall is:
A rectangular tank measuring 5m x 4.5 m x 2.1 m is dug in the centre of the field measuring 13.5.m x 2.5. The earth dug out is spread evenly over the remaining portion of afield. How much is the level of the field raised ?