Pipes A and B can fill a tank in 12 minutes and 15 minutes, respectively. The tank when full can be emptied by pipe C in x minutes. When all the three pipes are opened simultaneously, the tank is full in 10 minutes. The value of x is:

Select theoption that is related to the fifth number in the same way as the second number is related to the first number and the fourth number is related to the third number.

13 : 195 :: 7 : 63 :: 18 : ?

Which helpline has been made functional by the Indian Railways to answer inquiries, provide assistance and also take suggestions during the 21-day lockdown due to COVID-19?

Study the given pattern carefully and select the number that can replace the question mark (?) in it.
 First row: 73, 52, 75
 Second row:64, 41, 63
 Third row: 68, 47, ?

(NOTE: Operations should be performed on the whole numbers, without breaking down the number into its constituent digits. For example, 13 – Operations on 13 such as adding/deleting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

Select the option that can be used as a one-word substitute for the given group of words.
 Story of an individual written by himself

Select the option that is related to the fifth term in the same way as the second term is related to the first term and the fourth term is related to the third term.
 DETAILS : TEDASLI :: EMPATHY : PMEAYHT :: FORMULA : ?