let x = total bill
t = number of texts
Josephs would be X = 20 +0.10t
Micki is X=10 + 0.15t
10+0.15t = 20 +0.10t
20+ .1t-.15t = 10
20+-05t=10
-.05t=-20+10
-.05t=-10
-10/-.05 = 200
t = 200
so 200 texts and the plans would equal the same
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