Maths Maths Puzzle Numerical Ability Time and Work

Two pipes P1 and P2 can fill a tank in 24 minutes and 30 minutes respectively. If both the pipes are opened simultaneously, after how much time should P2 be closed so that the tank is full in 20 minutes ?

Read Solution (Total 2)

5 minutes

If P2 is closed after 'x' minutes, then upto 'x' minutes both P1 and P2 are opened and after 'x' minutes only P1 will be opened.
So 'x' minutes filling by P1 & P2+(20-x) minutes filling by P1=complete filling of tank
x[(1/24)+(1/30)] + x(1/24)=1
On solving, x=5
9 years agoHelpfull: Yes(2) No(0)

x[(1/24)+(1/30)]+[20-(x*1/24)]=5
so answer is 5
9 years agoHelpfull: Yes(0) No(0)

Maths Other Question

If a^2+b^2+c^2 = 36, x^2+y^2+c^2 = 25 and ax+by+cz = 30 then the value of ( x+y+z /a+b+c) is The marketing research organization conducts a yearly survey on consumer attitudes worldwide. They collect demographic information on the roughly 1500 respondents from each country that they survey. Here is a table showing the number of people with various levels of education in five countries:
PostGraduate College HighSchool Primary Noanswer Total
China 7 315 671 506 3 1502
France 69 388 766 309 7 1539
India 161 514 622 227 11 1535
U.K 58 207 1240 32 20 1557
U.S.A 84 486 896 87 4 1557
Total 379 1910 4195 1161 45 7690
If we select someone at random from this survey
a) What is the probability that the person is from the United States?
b) What is the probability that the person completed his or her education before college?
c) What is the probability that the person is from France or did some post-graduate study?
d) What is the probability that the person is from France and finished only primary school or less?
e) Given that the respondent is post-graduate what is the probability that the respondent is from U.S.A?
f) Given that the respondent is form U.K what is the probability that he/she has a high school diploma?
g) What is the probability that a respondent who only a primary-level education is from China?
h) What’s the probability that a respondent from china has only primary level education?