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In the following questions an equation followed by some information is given. Read the equation and information carefully to answer the given questions.
x2 + 18x + P = 0.
Roots of the above equation are m and n and where m2 – n2 = –108 .
Find the value of P.
Given equation: x2 + 18x + P = 0
After comparing the given equation with x2 – (Sum of roots)x + (Products of roots) = 0
Sum of the roots (m and n) = –18
So, m + n = –18 …..(1)
And m2 – n2 = –108
(m + n)(m – n) = –108
–18 × (m – n) = –108
m – n = 6 …..(2)
After solving both the equations, we get:
m = –6, n = –12
The value of P = (–6) × (–12) = 72
Find the value of P + 2m – n2.
Required value = P + 2m – n2
= 72 + 2 × (–6) – (–12)2
= 72 – 12 – 144 = –84
In the following question two equations are given in variables x and y. You have to solve these equations and determine relation between x and y.
Hence, x > y
I. 4x2 + 15x + 9 = 0
II. 15y2 + 11y + 2 = 0
I. 4x2+ 15x + 9 = 0 ⇒ 4x2+ 12x + 3x + 9 = 0 ⇒ 4x(x + 3) + 3(x + 3) = 0 ⇒ (4x + 3)(x + 3) = 0 ⇒ x = –3 or –3/4 II. 15y2+ 11y + 2 = 0 ⇒ 15y2+ 5y + 6y + 2 = 0 ⇒ 5y(3y + 1) + 2(3y + 1) = 0 ⇒ (5y + 2)(3y + 1) = 0 ⇒ y = –1/3 or –2/5 Hence, x < y
Area of a square is 64 cm2 and the perimeter of a rectangle is 4 cm more than half of the perimeter of square. If the breadth of the rectangle is 4 cm and length of the rectangle is equal to the radius of a circle. Find the difference between the area and the circumference of the circle.
Area of square = 64 cm2
Side of square = 8 cm
Perimeter of square = 4 × 8 = 32 cm
According to the question ,
Perimeter of the rectangle = 4 + 32/2 = 20
2 × (length + breadth) = 20 cm
Length = 10 – 4 = 6 cm
Length = radius of circle = 6 cm
Area of circle – circumference of circle = Πr2 – 2Πr = 36Π – 12Π = 24Π
Two persons A and B start simultaneously from same point in the same direction and distance between them after 30 minutes becomes 16 km, then what will be the distance between them when they travel in opposite direction for the same time period and ratio of their speeds is 3 : 2?
Let the speed of A and B is '3x' and '2x' respectively.
Relative speed of both the persons when travelling in same direction = 3x − 2x = x
relative speed of both the persons when travelling in opposite direction = 3x + 2x = 5x
According to the data in the question,
Also, we can observe that if in half an hour 16 km is covered with speed x. Then in the same with speed 5x, 80km will be covered.
In a monthly test of maths total marks scored by Satish, Varun and Saumya is 245. The ratio of the marks scored by Satish and Saumya is 5 : 6 and that of the marks scored by Saumya and Varun is 9 : 8. Find the total marks scored by Satish in the maths.
Ratio of marks of Satish and Saumya = 5 : 6
Ratio of marks of Saumya and Varun = 9 : 8
Ratio of the marks scored by Satish, Saumya and Varun respectively
= 5 × 9 : 6 × 9 : 6 × 8
= 45 : 54 : 48 = 15 : 18 : 16
∴ Marks scored by Satish
In how many different ways, can the letters of the word ‘FLAVOUR’ be arranged in such a way that the vowels always come together?
In the word FLAVOUR:
Vowels are – A, O, U (3)
consonants are – F, L, V, R (4)
Required number of ways = (4 + 1)! × 3! = 120 × 6 = 720
The ratio of milk and water in a mixture of 90 liter milk and water is 7 : x. If 15 liter of water is added in the mixture, the ratio of water to milk becomes 1 : x, then find the quantity of milk in the initial mixture.
⇒ (105x + 105)x = 1 × 630
⇒ (x + 1)x = 6
⇒ x2 + x − 6 = 0
⇒ (x + 3)(x − 2) = 0
⇒ x = 2
The MRP of a article is 50% more than its manufacturing cost. The article is sold through a retailer, who earns 25% profit on his purchased price. What is the profit or loss percentage of the manufacturer who sells his article to the retailers, If the retailers give 20% discount on MRP?
Let manufacturing cost be Rs. 100.
Then, MRP = Rs. 150
Discount = 20%
Customer's price = Selling price of retailer = 0.8 × 150 = Rs. 120
Profit of retailer = 25% on purchased price
Let purchasing price of the retailer = Rs. a
According to question,
1.25a = 120 ⇒ a = Rs. 96
Selling price for manufacturer = Purchasing price of retailer = Rs. 96
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