Ascending order of the numbers 0.515, 0.5, 0.06, 0.52, 0.053 is :

Six bells start ringing simultaneously and they ring at intervals of 4, 8, 10, 12, 18 and 20 seconds respectively. Once the ringing starts, how many times will the bells ring together in next 30 minutes?

Find the number of factors of 60.

Three chocolate bars weighing 600 grams, 420 grams and 780 grams were cut into small pieces of uniform weight. If 2 such bars are given to one person, then what will be the minimum number of such persons between whom all the bars can be distributed?