If $ = −, % = ×, # = +, then 18 % 2 $ 3 # 1 = ?

Correct — B.
Rule: substitute $ = −, % = ×, # = +, then apply BODMAS.

18 % 2 $ 3 # 1 = 18 × 2 − 3 + 1
Multiply first: 18 × 2 = 36
Then left to right: 36 − 3 + 1 = 34

The value is 34 → option (b).

Why the others are wrong

• (a)
  33 — 33 stops at 36 − 3 and drops the # 1. The + 1 still applies, giving 34.
• (c)
  32 — 32 is 36 − (3 + 1): it adds before subtracting. With no brackets, − and + go left to right, so 36 − 3 = 33, then 33 + 1 = 34.
• (d)
  35 — 35 matches no bracketing of 18 × 2 − 3 + 1. Worked in the right order, the value is 34.

After substitution the expression is 18 × 2 − 3 + 1. Multiplication comes first, giving 36. Then − and + share one level and are worked left to right: 36 − 3 = 33, and 33 + 1 = 34.

BODMAS lists A before S, but addition and subtraction have equal rank. Reading it as + before − gives 32 instead.

Key facts

• In this item $ = −, % = × and # = +.
• Addition and subtraction have equal rank and are worked left to right.
• 18 × 2 − 3 + 1 = 36 − 3 + 1 = 34.

Common traps

• Doing 3 + 1 first and getting 32
• Dropping the last term and stopping at 33

No directly related past PYQ was found.