A certain weight (in kg) is divided into two parts such that 5 times the first part added to 11 times the second part makes 7 times the whole weight. The ratio of the first part to the second part is :
Answer & explanation
Correct answer: option 3
Let first and second part of the number be x and y, respectively. Then,
5x + 11y = 7 (x + Y)
11y - 7y = 7x - 5x
4y = 2x
x : y = 2 : 1