Start by defining your variables
let x be the mass of a single mango in gm
let y be the mass of a single orange in gm
now, write the question as a system of equations
3 mango and 2 orange have a mass of 200 gm
3x +2y = 200
4 mango and 4 orange have a mass of 300 gm
4x +4y = 300
now you have a system of equations
3x+2y =200
4x+4y =300
solve for x and y
Multiply the person's weight (9 stone) by the conversion factors (14 lb / 1 stone) and (1 kg / 2.2 lb). Please show your work.