question 13 of 25\nif the pattern below follows the rule \starting with 10, every consecutive line has a…

question 13 of 25\nif the pattern below follows the rule \starting with 10, every consecutive line has a number 1 less than the previous line,\ how many marbles must be in the seventh line?\na. 7\nb. 4\nc. 6\nd. need more information

question 13 of 25\nif the pattern below follows the rule \starting with 10, every consecutive line has a number 1 less than the previous line,\ how many marbles must be in the seventh line?\na. 7\nb. 4\nc. 6\nd. need more information

Answer

Explanation:

Step1: Define the sequence rule

This is an arithmetic sequence where first term $a_1 = 10$, common difference $d = -1$. The nth term formula is $a_n = a_1 + (n-1)d$.

Step2: Plug in n=7 for 7th line

Substitute $a_1=10$, $n=7$, $d=-1$ into the formula: $a_7 = 10 + (7-1)(-1)$

Step3: Calculate the result

Simplify the expression: $a_7 = 10 - 6 = 4$

Answer:

B. 4