There are three kinds of goods A, B, and C. If you buy 3 pieces of A, 7 pieces of B, and 1 piece of C, the total cost is 3.15 yuan; if you buy 4 pieces of A, 10 pieces of B, and 1 piece of C, the total cost is 4.20 yuan. Now someone buys A, B, and C each, how much does he spend in total?
甲、乙、丙三种货物，如果购买甲3件、乙7件、丙1件共花3.15元；如果购买甲4件、乙10件、丙1件共花4.20元．现有人购得甲、乙、丙各1件，他共花多少元．
<result>1.05</result>