Days for fewer men to finish double the work
15 days
💡 What it's asking: Measure the job in man-days, double it, then share it among 8 men.
- Original job: 10 × 6 = 60 man-days.
- Double job: 120 man-days.
- 8 men: 120 ÷ 8 = 15 days.
✅ 8 men × 15 days = 120 man-days, twice the original 60.
සිංහලෙන් විසඳුම
කාර්යය මිනිස් දිනවලින් මැන, දෙගුණ කර, මිනිසුන් 8 අතර බෙදන්න.
- මුල් කාර්යය: 10 × 6 = මිනිස් දින 60.
- දෙගුණ කාර්යය: මිනිස් දින 120.
- මිනිසුන් 8: 120 ÷ 8 = දින 15.
Factorise a trinomial with leading coefficient 2
(x + 2)(2x - 3)
💡 What it's asking: With a 2 in front of x², multiply 2 by −6 first, then split the middle term.
- 2 × (−6) = −12; need two numbers multiplying to −12 and adding to 1: 4 and −3.
- Rewrite: 2x² + 4x − 3x − 6.
- Group: 2x(x + 2) − 3(x + 2) = (x + 2)(2x − 3).
✅ (x + 2)(2x − 3) = 2x² − 3x + 4x − 6 = 2x² + x − 6. Correct.
සිංහලෙන් විසඳුම
x² ඉදිරියේ 2 ඇති නිසා මුලින් 2, −6 න් ගුණ කර මැද පදය බෙදන්න.
- 2 × (−6) = −12; ගුණිතය −12 හා එකතුව 1 වන සංඛ්යා: 4 සහ −3.
- නැවත ලියන්න: 2x² + 4x − 3x − 6.
- කාණ්ඩ කරන්න: 2x(x + 2) − 3(x + 2) = (x + 2)(2x − 3).
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