Evaluate using Pascal's triangle. ${ } _ { 7 } C _ { 4 }$
A) ${ } _ { 7 } C _ { 4 } = 840$
B) ${ } _ { 7 } C _ { 4 } = 70$
C) ${ } _ { 7 } C _ { 4 } = 126$
D) ${ } _ { 7 } C _ { 4 } = 15$
E) ${ } _ { 7 } C _ { 4 } = 35$

Question

Evaluate using Pascal's triangle.​ ${ } _ { 7 } C _ { 4 }$ ​
A) ${ } _ { 7 } C _ { 4 } = 840$
B) ${ } _ { 7 } C _ { 4 } = 70$
C) ${ } _ { 7 } C _ { 4 } = 126$
D) ${ } _ { 7 } C _ { 4 } = 15$
E) ${ } _ { 7 } C _ { 4 } = 35$

Quizplus · Accepted Answer

${ } _ { 7 } C _ { 4 }$ calculates the number of combinations of 7 items taken 4 at a time. Using Pascal's triangle, the 7th row (starting with row 0) has the values 1, 7, 21, 35, 35, 21, 7, 1. The 4th value (starting from 0) is 35.

Evaluate Using Pascal's Triangle 7C4{ } _ { 7 } C _ { 4 }7​C4​

Evaluate Using Pascal's Triangle ${ } _ { 7 } C _ { 4 }$