Answer:
126 g
Step-by-step explanation:
Sum the parts of the ratio, 7 + 3 = 10 parts
Divide the quantity of flour by 10 to find the value of one part of the ratio
420g ÷ 10 = 42g ← value of 1 part of the ratio, thus
3 parts = 3 × 42g = 126g ← smaller amount