Multiple choice

In the question given below, use the following notations : A " B means 'add B to A'; A ' B means 'subtract B from A'; A @ B means 'divide A by B'; A ★ B means 'multiply A by B'; Now, answer the following question. The time taken by two running trains in crossing each other is calculated by dividing the sum of the lengths of two trains by the total speed of the two trains. If the length of the first train is $L_1$, the length of the second train is $L_2$, the speed of the first train is $V_1$ and the speed of the second train is $V_2$, which of the following expressions would represent the time taken ?

  1. ($L_1$ "$L_2$) $\bigstar $ ($V_1$ "$V_2$)
  2. ($L_1$ "$L_2$) @ ($V_1$ "$V_2$)
  3. [($L_1$ "$L_2$) @ ($V_1$ "$V_2$)] $\bigstar $ 60
  4. ($L_1$ '$L_2$) @ ($V_1$ '$V_2$)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The time taken is (L1 + L2) / (V1 + V2). Using the provided notation, L1 + L2 is (L1 " L2) and V1 + V2 is (V1 " V2). Dividing these gives (L1 " L2) @ (V1 " V2).

AI explanation

Using the provided notations, the sum of the lengths is L1 " L2, and the sum of the speeds is V1 " V2. Because the time is found by dividing the total length by the total speed, the correct expression is (L1 " L2) @ (V1 " V2).

Keep practicing — related questions