The original price was 7.
Chloe got a 15% discount; this means she paid 100-15 = 85% of the price. Letting x be the price, Chloe paid 0.85x.
Denise got a 20% discount; this means she paid 100-20 = 80% of the price. Denise paid 0.8x.
We know that Chloe paid 35p more; this gives us the equation
0.85x = 0.8x + 0.35
We do not want a variable on both sides, so we subtract 0.8x from both:
0.85x - 0.8x = 0.8x + 0.35 - 0.8x
0.05x = 0.35
Divide both sides by 0.05:
0.05x/0.05 = 0.35/0.05
x = 7