请教一道小五的数学题,求高手帮忙

请教一道小五的数学题，实在的伤脑筋，请高手帮助，最好有解题过程，谢谢。

Alvin and Ken earned $6425 altogether .1/5 of Alvin’s monthly salary was $75 more than 1/6 of Ken’s monthly salary.How much money did Alvin earn each month?

感激涕零啊，谢谢。