Answer:
In 10 weeks
Step-by-step explanation:
Supposing the bank does not pay any interest, after n weeks Katie will have
$710 - n35
and Diana will have
$570 - n25
We must find then a number n such that
710 - n35 = 570 - n25
Isolate n
710 - 570 = n35 - n25
140 = 10n
Hence
n = 140/10 = 14
So, Katie and Diana will have the same amount of money after 14 weeks.