Question
Average weight of a group of ‘x’ people increased by
2 kg, when a person weighing 70 kg joined the group, while the average weight increased by 3 kg when two persons weighing 68 kg each joined the group. Find the value of ‘x’.Solution
Number of people in the group = ‘x’
Let, average weight of each person in the group be ‘y’ kg
Total weight of all the persons in the group = x × y = ‘xy’ kg
ATQ,
(xy + 70) = (x + 1) × (y + 2)
Or, xy + 70 = xy + y + 2x + 2
Or, y + 2x = 68 ------------(I)
Also,
(xy + 68 × 2) = (x + 2) × (y + 3)
Or, xy + 136 = xy + 2y + 3x + 6
Or, 2y + 3x = 130 ------------(II)
Putting value of ‘y’ from equation (I) in equation (II), we get
y = 68 – 2x
So, 2(68 – 2x) + 3x = 130
Or, 136 – 4x + 3x = 130
Or, –x = –6
So, x = 6
So, value of ‘x’ = 6
95.001% of 8219.99 - 4/9 % of 5399.98 + 109.99 = ?
25.05% of 220.05 – 10.15% of 119.99 × 2.02 = ?
What approximate value should come in the place of (?) in the following questions?
∛(92.8 + √1025) * ? = 16.06% of 750
What approximate value should come in the place of (?) in the following questions?
?3 -18.32 * 40.24 ÷ √399 = 200.79 + 105.78
...1080.04 – 250.18 + 199.98 ÷ 20.06 = ?
What approximate value should come in the place of (?) in the following questions?
9.9 * [? – (4.9 * √576 ÷ 7.80)] = 950.05
108.31% of (4.9/9.012) of ? = 23.9% of 2499.9
22.11 × 4.98 + 23.03 × 5.12 – 32.95 + 96.9 × 5.02 =?
(√8648 ×7) ÷ (3.9 ×5.99) = ?
6527.83 - 4891.21 + 7423.46 + ? = 14520.34
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