What was the total number of stars received by D?
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Correct answer: 45
Each of the six surfers hands out exactly 30 stars (all in multiples of 5) among bloggers A, B, C and D. The chart fixes how many went to A and B; each surfer's stars to C and D together must therefore be .
Totals must be equal. The six surfers give stars in all, and every blogger ends with the same total, so each blogger got . Adding the chart columns, A already has and B has — so C and D must also reach 45 each.
Now pin the remaining cells:
- Surfer Y: Y gave 5 to A and 20 to B, leaving 5 for C and D. We're told D got more than C, so .
- Surfer M: the clue says M gave a different amount to each blogger. M gave 10 to A and 0 to B, and C+D must be 20 with two different values (not 0 or 10) — so they are 5 and 15.
- Two surfers gave everything to one blogger. Only O and X gave nothing to A or B, so they are the two who dump all 30 on a single blogger. C and D each still need 45, and O and X supply 60 between them — so one of them goes entirely to C and the other entirely to D (which one is not fixed).
- Balancing C: C needs 45. One of O/X supplies 30, Y supplies 0, so M and N must supply the other 15. That forces M gives C = 15 (so D = 5) and N gives C = 0 (so D = 5).
This gives the full grid (the only open point is whether O→C & X→D, or the reverse):
| Surfer | A | B | C | D | Total |
|---|---|---|---|---|---|
| M | 10 | 0 | 15 | 5 | 30 |
| N | 25 | 0 | 0 | 5 | 30 |
| O | 0 | 0 | 30 or 0 | 0 or 30 | 30 |
| P | 5 | 25 | 0 | 0 | 30 |
| X | 0 | 0 | 0 or 30 | 30 or 0 | 30 |
| Y | 5 | 20 | 0 | 5 | 30 |
| Total | 45 | 45 | 45 | 45 | 180 |
This question — total stars received by D. Every blogger's total is the same, and . Reading D's column confirms it: (whichever of O/X feeds D).
Answer: 45