51/3-(1/10 + 2/15) ÷1/25

51/3 - (1/10 + 2/15) : 1/25
= 51/3 - (3/30 + 4/30) : 1/25
= 51/3 - 7/30 x 25/1
= 51/3 - 175/30
= 510/30 - 175/30
= 335/30
= 11 5/30
= 11 1/6