Answer
Day $11$
Work Step by Step
Day $1$:
Total items: $50+32=82$
Peanuts percent: $\frac{50}{82}\times\approx 60.98\%$
Day $11$:
Total items: $56+26=82$
Peanuts percent: $\frac{56}{82}\times\approx 68.29\%$
Day $21$:
Total items: $48+34=82$
Peanuts percent: $\frac{48}{82}\times\approx 58.54\%$
Day $31$:
Total items: $52+30=82$
Peanuts percent: $\frac{52}{82}\times\approx 63.41\%$
Only Day $11$ met the specification of $65\%$ to $69\%$ peanuts.
