Let original price = 100 and quantity sold = 100.
Original revenue = 100 × 100 = 10,000.
New price = 80, new sales = 160.
New revenue = 80 × 160 = 12,800.
Increase in revenue = (12,800 − 10,000)/10,000 × 100 = 28%.
Months with same number of days:
- May (31) and January (31) ✅ same
- September (30) and November (30) ✅ same
- October (31) and April (30) ❌ different
- January (31) and December (31) ✅ same
Hence, “October : April” is the odd one out.
Check each ‘8’:
1️⃣ 7 8 9 → preceded by 7 and followed by 9 ❌
2️⃣ 9 8 8 → preceded by 9, followed by 8 ✅
3️⃣ 8 5 4 → ✅
4️⃣ 5 8 8 → ✅
5️⃣ 8 7 1 → ❌ followed by 7
6️⃣ 7 1 8 9 → ❌ (preceded by 7, followed by 9)
So valid 8’s = 3
Rule → add $+4$ to each letter. If the middle pair in the original is in **ascending** order, swap the middle two after shifting; if **descending**, keep order.
$MNPQ$ (middle $N
G$: descending): $+4 \Rightarrow \boxed{JMKT}$ (no swap).