(B)笑笑用13.6元买了20枚6角和8角的邮票,6角和8角的邮票各有多少枚?

问题描述:

(B)笑笑用13.6元买了20枚6角和8角的邮票,6角和8角的邮票各有多少枚?

设6角的邮票x枚,那么8角的邮票就为(20-x)枚
0.6x+0.8×(20-x)=13.6,
              0.2x=2.4,
                 x=12;
则20-x=20-12=8.
答:6角的邮票12枚,8角的邮票8枚.