НГ Николай Гусаров Да легко: 1/1*6+1/6*11+1/11*16+1/16*21+1/21*26+1/26*31+1/31*36+1/36*41+1/41*46+1/46*51+1/51*56+1/56*61+1/61*66+1/66*71+1/71*76 = 22,97708005549