1. Problem 1: Find the weekly interest rate in kobo per naira if ₦20 becomes ₦35 in 5 weeks. Step 1: Set the principal \(P = 20\) naira, amount \(A = 35\) naira, time \(t = 5\) weeks. Step 2: Use the simple interest formula \(A = P + P \, r \, t\) where \(r\) is the interest rate in naira per naira per week. Step 3: Rearrange for \(r\): $$r = \frac{A - P}{P t} = \frac{35 - 20}{20 \, \times \, 5} = \frac{15}{100} = 0.15 \text{ naira per naira per week}$$ Step 4: Convert to kobo per naira per week (1 naira = 100 kobo): $$0.15 \times 100 = 15 \text{ kobo per naira per week}$$ 2. Problem 2: Find the duration in weeks for a loan of ₦200 at 12k per naira per week that amounts to ₦344. Step 1: Principal \(P = 200\), rate \(r = 12\) kobo = \(0.12\) naira per naira per week, amount \(A = 344\). Step 2: Use \(A = P + P r t\). Rearranged: $$t = \frac{A - P}{P r} = \frac{344 - 200}{200 \times 0.12} = \frac{144}{24} = 6 \text{ weeks}$$ 3. Problem 3: Find the amount to borrow to get a take-home profit of ₦250 each day, given: - Gains 20k (0.20 naira) per naira spent on bread - Spends ₦50 on food daily - Interest charged is 10k (0.10 naira) per naira per day Step 1: Let amount borrowed be \(x\) naira. Step 2: Profit from bread = \(0.20 x\) naira Step 3: Interest cost = \(0.10 x\) naira Step 4: Total take-home profit after food and interest: $$\text{Profit} = 0.20 x - 50 - 0.10 x = 0.10 x - 50$$ Step 5: Set \(0.10 x - 50 = 250\) and solve for \(x\): $$0.10 x = 300 \implies x = \frac{300}{0.10} = 3000 \text{ naira}$$