Naresh bought two bicycles, each costing Rs. 3500, so the total cost is Rs. 7000. The first is sold at a 5% profit. We need the profit percentage on the second bicycle so that the overall profit across both bicycles is 20%. Let's check each option by computing the total profit it would produce.
Only a 35% profit on the second bicycle brings the overall profit on both bicycles to the required 20%.
Therefore, the correct answer is 35%.
Naresh's total cost for both bicycles is \( 3500+3500=7000 \). For an overall profit of 20%, the total profit needed is \[ 0.20\times7000=1400. \] The first bicycle, sold at 5% profit, earns a profit of \[ 0.05\times3500=175. \] The profit still needed from the second bicycle is therefore \[ 1400-175=1225, \] and as a percentage of its own cost price of 3500, this is \[ \frac{1225}{3500}\times100=35\%. \] Check each option against this required profit of Rs. 1225 on the second bicycle.
Subtracting the first bicycle's actual profit from the total profit required for a 20% overall gain shows the second bicycle must earn Rs. 1225, which corresponds to a 35% profit.
Therefore, the correct answer is 35%.
