Pythagorean theory baby! Okay so the Pythagorean theory is a² + b² = c² so lets draw a triangle and label our sides. So we know 8² + 15² = c² so I'm going to find the square root of all of our numbers. We get 64 + 225 = c² so then add 64 + 225 = 289 then I take the square root of 289 which equals 17 . This answer also makes sense because out hypotenuse should always be bigger then the legs.
Set x is amount of money in first account => x + 2000 is money in second account. X*3% + (x+2000)*4% = 535 => x = (53500 - 8000) / 7 X = 45500 / 7 = 6500 => account #1 = x = 6500 Acc #2 = x + 2000 = 6500 + 2000 = 8500