‘X’ grams contain nine gram atoms of calcium. ‘X’ grams contain ‘Y’ gram atoms of magnesium. The value of 'Y' is

‘1’ gram atom of ‘Ca’ = 40 g ;‘9’ gram atoms of ‘Ca’ = 360 g ;‘X’ = 360 g ;  ‘1’ gram atom of ‘Mg’  = 24 g ;‘Y’ gram atoms of ‘Mg’ = 360 g (X);                                 Y = 15 ;