Bright Zoom Maths

 Aptitude Solved Problems - Profit and Loss  1. A trader mixes 26 kg of rice at Rs. 20 per kg with 30 kg of rice of other variety at Rs. 36 per kg and sells the mixture at Rs. 30 per kg. Find his profit percent ?  Answer: 5 %  Explanation:  Cost Price of 26 kg of rice = ( 26 * 20 )  = Rs. 520  Cost Price of 30 kg of rice = ( 30 * 36 )  = Rs. 1080  Cost Price of 56 kg rice = Rs. ( 520 + 1080 )  = Rs. 1600  Selling Price of 56 kg rice = Rs. ( 56 * 30 )  = Rs. 1680  Gain = Selling Price - Cost Price  = 1680 - 1600  = 80  Gain % = ( Gain * 100 ) / Cost Price  = ( 80 * 100 ) / 1600  = ( 8000 / 1600 )  = ( 80 / 16 )  = 5 %  2. Vimal bought paper sheets for Rs. 7200 and spent Rs. 200 on transport. Paying Rs. 600, he had 330 boxes made, which he sold at Rs 28 each. Find his profit percentage ?  Answer: 15.5 %  Explanation  Total investments ( Cost Price ) = ( 7200 + 200 + 600 ...

Tricks to multiply a number by 39 Example: 1 26 * 39 Step 1: Multiply 26 by 4 26 * 4 = 104 Step 2: Multiply 104 by 10 104 * 10 = 1040 Step 3: Subtract 26 from 1040 1040 - 26 = 1014 26 * 39 = 1014  Example: 2 125 * 39 Step 1: Multiply 125 by 4 125 * 4 = 500 Step 2: Multiply 500 by 10 500 * 10 = 5000 Step 3: Subtract 5000 from 125 5000 - 125 = 4875 125 * 39 = 4875 Example: 3 342 * 39 Step 1: Multiply 342 by 4 342 * 4 = 1368 Step 2: Multiply 1368 by 10 1368 * 10 = 13680 Step 3: Subtract 342 from 13680 13680 - 342 = 13338 342 * 39 = 13338