Number of candidates who passed in either section but not in both | 2450 |
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Solution
\(\frac{35}{100}\) × 5000 = 1750 failed in Maths
\(\frac{42}{100}\) × 5000 = 2100 failed in verbal
\(\frac{15}{100}\) × 5000 = 750 failed in both
∴ 1750 -750 = 1000 failed only in Maths
Similarly, 2100 - 750 = 1350 failed only in Verbal
Number of candidates who failed only in Maths = Number of candidates who passed only in Verbal.
∴ Col. A = 1000 + 1350 = 2350
speed of the stream ill kmph | 3.5 |
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Solution
Let speed of stream be y kmph.
∴ Upstream speed = 10 - Y
Downstream speed = 10 + Y
Time = \(\frac{Distance}{Speed}\)
t upstream = t downstream
∴ \(\frac{14}{10-y}=\frac{26}{10+y}\)
∴ 7(10 + y) = 13(10 - y)
∴ 70 + 7y = 130 - 13y
∴ 20y = 60 ∴ y = 3 km/hr.
c | 12 |
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Solution
a + b + C = 24 ⇒ 2c + b = 24
∴ b = 24 - 2c
If c = 12, then b = 0, which is not true as b is positive
∴ 'c' can take a maximum value which is 11.
speed of joe in kmph | 4.5 |
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Solution
Time × Speed = Distance
Speed = x km per hour.
∴ 30x - 30\(\left (\frac{14x}{15} \right )\) = 10
∴ 2x = 10,x = 5 = Col.A
Sum lent by Mark in $ | $4000 |
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Solution
Amount after 3 years and 7 years is $6200 and $7800 respectively
Amount = P + S.I.
Let the sum be P
∴ P + 8.I3 years = $6200
∴ S.I.2 years=$7800
∴ S.I·4 years = $7800- $6200 = $1600
∴ S·I.3 years = $1200
∴ P + $1200 = $6200 ∴ P = $5000
The number of days, by which the work would have delayed if these additional number of men had not been employed | 2 |
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Solution
In the first 25 days, 30 men do 30 × 25 = 750 units of work. 5 more men were employed and work was completed 1 day earlier.
∴ After 25 days, (30 + 5) men worked for (13 - 1) days.
∴ They produced 35 × 12 = 420 units of work.
∴ Total work content = 750 + 420 = 1170 units of work.
In the absence of additional number of men, work would be completed in \(\frac{1170}{30}\) = 39 days.
∴ The work would take 1 day more
Col. A = 1, Col. B = 2
Value of n if m2 – 2mn + n2 = 0 | Value of p if m2 + 2mp + p2 = 0 |
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Solution
Col. A:
m2 - 2m + n2 =0
∴ m - n = O ∴ m = n
∴ (m-n)2 = 0
∴ n > 0
Col. B:
m2 + 2mp + p2 = 0
∴ (m + p)2 =O ∴ m + p = O
∴ m = -p
But m > 0 ∴ - p > 0 ∴ p < 0 ∴ Col. A is positive, Col. B is negative
LCM of ax & by | ax × by |
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Solution
a and b are prime numbers (i.e. they have only number 1 in common)
∴ Higher powers of a and b i.e. ax and by will be co-prime numbers (only factor 1 in common).
E.g. if 3 and 5 are distinct primes, then 33, 52 are co-prime numbers.
LCM of co-prime numbers = product of numbers.
∴ LCM of ax, by = ax x by
Value of the quotient if dividend is divided b remainder | 21 |
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Solution
The remainder = 7
∴ Divisor = 7 × 3 = 21
∴ Dividend = 21 × 4⁄3 = 28
∴ Col.A =\(\frac{28}{7}\)= 4, Col.B = 21
A square PQRS is inscribed in a circle with centre M. Area of ΔRMS = 18, ∠RMS = 90°
Area of shaded region | 48 |
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Solution
RMS is an isosceles right angled triangle.
∴ 18 = \(\frac{(RM)^{2}}{2}\) ∴(RM) = 6
Radius of circle = 6 ∴ Area = 36π
∴ Area of square = 18 × 4 = 72
∴ Col. A = 361π -72 = 36(π - 2} = 36 × 1.142
Col. B = 45 = 36 × 1.25