Question
Machine P can print one lakh books in 8 hours, machine Q
can print the same number of books in 10 hours while machine R can print them in 12 hours. All the machines are started at 9 A.M. while machine P is closed at 11 A.M. and the remaining two machines complete work. Approximately at what time will the work (to print one lakh books) be finished?Solution
The efficiency of P is 1/8 The efficiency of Q is 1/10 The efficiency of R is 1/12 Work done by P + Q + R in one hour ⇒ 1/8 + 1/10 + 1/12 = (15 + 12 + 10)/120 ⇒ 37/120 P, Q and R work for two hours 9 A.M to 11 A.M ⇒ 37/120 × 2 = 37/60 Remaining work is ⇒ 1 - 37/60 = 23/60 ⇒ Work done by Q and R in an hour ⇒ 1/10 + 1/12 = 11/60 Now time taken to complete the remaining work ⇒ (23/60) ÷ (11/60) ⇒ (23/60) × (60/11) = 23/11 ≈ 2 hours So add 2 hours in 11 A.M we get 1 P.M ∴ The correct answer is 1 P.M
If 2x = cosec @ and 4/x = cot @ then the value of 2(x ² - 1/x ² ) is
(tan 5x - tan 3x - tan 2x) = ?
If tan 4θ = cot 14θ, then find the value of cos 9θ.
- If sin (a + b) = (√3/2) and cos (a – b) = (√3/2), then find sin a.
If tan θ + cot θ = 2 where 0 < θ < 90 ; find the value of tan17 θ + cot19 θ.
Solve the following trigonometric expression:
- If sin 2 Â A + sin 4 Â A = 1 and cos 2 Â A + cos 4 Â A = 1, then find the value of (sin 4 Â A - cos ...
If (5sinx - cosx) = 2√2sinx, then find the value of 'tanx'
If A, B and C are angles of triangle, then sin2A + sin2B + sin2C– 2cosA cosB cosC
sin2 17˚ + sin2 19˚ + sin2 21˚ + sin2 23˚ + ……… + sin2 77˚ = ?
Relevant for Exams:
