Dan spent 15% of his savings on a new phone, it means he spent 15/100 * x = 0.15x.
We are given that he spent $150 on the new phone, so we can set up the equation:
0.15x = $150
To solve for x, we divide both sides of the equation by 0.15:
x = $150 / 0.15
x = $1000
Therefore, Dan had $1000 in savings before buying the new phone.