Consider two events <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/a8ea75305f9f471fac6505b6e289d3cc.png?x-oss-process=image/sharpen,200"/> and <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/60cf36359bda4978a54f12e9b8eeb49b.png?x-oss-process=image/sharpen,200"/> such that <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/ed987afd231b446b8949487cec31d24f.png?x-oss-process=image/sharpen,200"/> and <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/2ce2bf6e97e24ecb84a230d8bbb59ba2.png?x-oss-process=image/sharpen,200"/>. Determine the value of <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/7cf5a7327b474ea7bfb6dd23677fcbc4.png?x-oss-process=image/sharpen,200"/> if <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/a8ea75305f9f471fac6505b6e289d3cc.png?x-oss-process=image/sharpen,200"/> is a subset of <img src="http://jgxm-question.oss-cn-beijing.aliyuncs.com/psst/files/60cf36359bda4978a54f12e9b8eeb49b.png?x-oss-process=image/sharpen,200"/>.