Question
A boat takes 5 hours longer to travel 15 km upstream
than it does to travel 20 km downstream. The speed of the boat in still water is 5 km/hr. Calculate the speed of the current.Solution
Let the speed of the current be x km/hr According to the question, 15/(5 β x) β 20/(5 + x) = 5 Or, x2Β + 7x β 30 = 0 Or, x2Β + 10x β 3x β 30 = 0 Or, x(x + 10) β 3(x + 10) = 0 Or, (x β 3) = 0 or, (x + 10) = 0 X = -10 km/hr not possible Therefore, x = 3 km/hr Hence, option b.
βAβ and βBβ invested Rs. 5000 and Rs. 4200, respectively in a business, together. After 7 months, βAβ withdrew 25% of his initial investment...
What will come in the place of question mark (?) in the given expression?
(14Β² + 10Β²) Γ· 8 β (9 Γ 5) = ?
If (3 Γ 144 β 252 Γ· 14) Γ· 18 = β1024 β x, then find the value of βxβ.
Evaluate: (936 Γ· 12) Γ (225 Γ· 15) β (144 Γ· 12) Γ 18
What will come in the place of question mark (?) in the given expression?
(72 Γ 4 β 92) Γ· 14 = ?
140% of 75 + 152 - 160 = ?
What will come in the place of question mark (?) in the given expression?
250% of...
25% of 160 × 18 = ? – 24
54% of 250 = 6 Γ 21 + β?
(1/2) β (3/5) + 3(1/3) = ? + (5/6)