Question

Difficulty: HardSets, Set Operations, and Venn Diagrams

In a survey of 120120 tech entrepreneurs at an innovation hub, 6565 secured Angel Investment (AA), 5555 received Venture Capital (VV), and 5050 obtained Government Grants (GG). Furthermore, 2525 received both AA and VV, 2020 received both VV and GG, 2222 received both AA and GG, while 1212 received no funding from any of these three sources. How many entrepreneurs secured funding from exactly two of these sources?

Answer: 52 entrepreneurs

Answer

The number of entrepreneurs who secured funding from exactly two sources is 52.
Subtracting the 1212 unfunded entrepreneurs from the total 120120 yields 108108 funded entrepreneurs. Applying inclusion-exclusion gives 108=65+55+50(25+20+22)+n(AVG)108 = 65 + 55 + 50 - (25 + 20 + 22) + n(A \cap V \cap G), which gives n(AVG)=5n(A \cap V \cap G) = 5. Subtracting 55 from each pairwise intersection yields 2020, 1515, and 1717 for entrepreneurs receiving funding from exactly two sources. Summing these gives 5252.

Step-by-Step Solution

1
Determine the cardinality of the union of all three funding sets
n(AVG)=108n(A \cup V \cup G) = 108
Subtracting the 12 unfunded entrepreneurs from the universal set of 120 gives the total number of entrepreneurs who received at least one form of funding.
2
Solve for the number of entrepreneurs who received funding from all three sources using inclusion-exclusion
n(AVG)=5n(A \cap V \cap G) = 5
Using n(AVG)=n(A)+n(V)+n(G)n(AV)n(VG)n(AG)+n(AVG)n(A \cup V \cup G) = n(A) + n(V) + n(G) - n(A \cap V) - n(V \cap G) - n(A \cap G) + n(A \cap V \cap G), we get 108=65+55+50252022+x108 = 65 + 55 + 50 - 25 - 20 - 22 + x, which simplifies to 108=103+x108 = 103 + x, giving x=5x = 5.
3
Calculate the count for each region representing exactly two funding sources
Only AV=20A \cap V = 20, Only VG=15V \cap G = 15, Only AG=17A \cap G = 17
Subtracting the 3-set intersection (x=5x = 5) from each pairwise intersection isolates the elements belonging to strictly two sets.
4
Sum the three strictly two-set regions
20+15+17=5220 + 15 + 17 = 52
Adding the individual counts for the three disjoint regions gives the total number of entrepreneurs who received funding from exactly two sources.

Key Concept

Principle of Inclusion-Exclusion for three sets and cardinal partitioning of Venn diagrams
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