Misha surveyed students in her school about what writing tool they use. She found that 75 use pens; 30 of the pen users are boys. She also found that 28 boys and 32 girls use pencils. A 4-column table with 3 rows. Column 1 has entries boys, girls, total. Column 2 is labeled pens with entries 30, a, 75. Column 3 is labeled pencils with entries 28, 32, b. Column 4 is labeled Total with entries c, d, e.

Determine what each letter should be to complete this two-way table.

a =
b =
c =
d =
e =