Question
I. 3x2 – 16x + 21 = 0 II.
y2 – 13y + 42 = 0 In each question two equations numbered (I) and (II) are given. You should solve both the equations and mark appropriate answer.Solution
I. 3x2 – 16x + 21 = 0 => 3x2 – 9x - 7x + 21 = 0 => 3x (x – 3) – 7 (x – 3) = 0 => x = 3, 7/3 II. y2 – 13y + 42 = 0 => y2 – 6y – 7y + 42 = 0 => y (y – 6) – 7(y – 6) = 0 => y = 7, 6 Hence, x < y Alternate Method: if signs of quadratic equation is - ve and +ve respectively then the roots of equation will be +ve and +ve. So, roots of first equation = x = 7/3, 3 So, roots of second equation = y = 7, 6 After comparing we can conclude that x < y.
βPβ can finish a task in 36 days, while βQβ can do the same task in (x + 4) days. If both work together and finish the task in 12 days, what is ...
Pβs 2 days work is equal to Qβs 5 days work. If P and Q together can complete the work in 30 days then how much time Q will take to complete 60% of ...
Ratio of the work done by P, Q and R in one day is 6:4:7 respectively. They all together can complete the work in 45 days. Q and R worked on it for 27 d...
Ashish and Anil can do a piece of work in 20 days and 28 days respectively. Ashish completed 75% of the work. Find the time taken by Anil to complete th...
Komal and Seema individually can complete a task in β5aβ hours and β7aβ hours respectively. If they together can complete (4/5)th of the work in...
B is 20% more efficient than A. If B was 60% more efficient than A, then, B could complete the work in 18 days lesser than days taken by A. What fractio...
'A' is 40% less productive compared to 'B', who is 25% more productive than 'C'. Together, they can finish a task in 45 days. After 'B' and 'C' have col...
Sudhir is 4.5 times as efficient as Aarav. If they work together, they can complete a piece of work in 9 days. How many days will Aarav take to do the s...
Puneet and Qureshi together can complete (7/8)th of a piece of work in 9 days, Qureshi and Rohit together can complete (3/5)th of the work in 8 days and...
X can do a piece of work in 36 days. He worked at it for 6 days and then Y finished it in 20 days. In how many days can X and Y together finish the work...