Question
βAβ and βBβ alone can do a certain work in 30
days and 40 days, respectively. Both started the work together but after βxβ days βAβ left the work and the rest work was completed by B alone in β2xβ days. Find the total time taken to complete the whole work in this way.Solution
Total work = 120 units (LCM of 30 and 40) Efficiency of βAβ = 120/30 = 4 units/day Efficiency of βBβ = 120/40 = 3 units/day According to the question, βAβ worked for βxβ days and βBβ worked for β2x days. Therefore, (4+3)x + 3 Γ 2x = 120 Or 7x + 6x = 120 Or x = 120/13 total time taken to complete the whole work = 3Γ120/13 =360/13 days =27.69days
Simplify the following expressions and choose the correct option.
{[(13)Β² β (7)Β²] Γ· 12} Γ 4 = ?
(25)Β² Γ 4 Γ· 5 + (3)Β³ + 48=? + 425
?2 + 114 - 48 Γ· 2 Γ 5 = 163
182 + 10 Γ 12 - ? = 312
2/5 of 3/4 of 7/9 of 7200 = ?
If (3 Γ 144 β 252 Γ· 14) Γ· 18 = β1024 β x, then find the value of βxβ.
12.50% of 1440 - 17 × 51 + 721 =?
[(15)³ × (8)²] ÷ (90 × 6) = ?²
?2 - (40% of 240) = 25 X 5
Simplify: 48 Γ· 4 Γ 3 + 5 Γ (6 β 2)