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← Expressions using Letter-Numbers

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Lesson 8 of 15

Writing an expression for a real situation

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7 min

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A cinema ticket costs ₹40. A ₹15 booking charge is added once, however many tickets you buy. Let t be the number of tickets.

Each ticket costs ₹40 — that part is 40t.
Step 1 of 3
  1. Each ticket costs ₹40 — that part is 40t.
  2. The booking charge, ₹15, happens once.
  3. Total = 40t + 15.

Rule: find the part charged per one, and the part charged once. Per one means for each ticket. Once means one time in all. The per-one part uses the letter. The once-only amount is added as a plain number.

Check it: 3 tickets cost 40 × 3 + 15 = 120 + 15 = ₹135.

Now an auto fare. The meter starts at ₹30. It adds ₹12 for each km (kilometre). For k km, the fare is 12k + 30. For 5 km, that is 12 × 5 + 30 = ₹90.

Pick a bill. Slide the count. Calculate the total, then use the rule.

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