Sasha sets a goal to read 5 minutes longer than each previous day for 30 days. On the first day, Sasha reads for 20 minutes. The
2 answers:
Let 
signify the number of pages that Sasha reads on day n
for instance,
represents the number of pages read on day 7.
On the first day, Sasha reads for 20 minutes, which translates to
minutes
minutes. Since she adds 5 minutes on each subsequent day
, we can compile the following enumeration:
Thus, it is clear that in 30 days, Sasha reads:
+
+
+...+
=
= 20 +(20+5)+(20+5*2)+(20+5*3)+...+(20+5*29)
In total, there are 30 sets of twenty plus 5 times the sum of integers from 1 to 29, simplifying to 5.
The sum of integers from 1 to 29 is calculated with Gauss's formula as (29*30)/2 = 435
. Therefore, the overall total is 20*30+435=600+435=1035 (minutes)
Note: Gauss's formula states that 1+2+3+...+(n-1)+n = n(n+1)/2
Result: 1035 minutes
for instance,
On the first day, Sasha reads for 20 minutes, which translates to
, we can compile the following enumeration:
Thus, it is clear that in 30 days, Sasha reads:
= 20 +(20+5)+(20+5*2)+(20+5*3)+...+(20+5*29)
In total, there are 30 sets of twenty plus 5 times the sum of integers from 1 to 29, simplifying to 5.
The sum of integers from 1 to 29 is calculated with Gauss's formula as (29*30)/2 = 435
. Therefore, the overall total is 20*30+435=600+435=1035 (minutes)
Note: Gauss's formula states that 1+2+3+...+(n-1)+n = n(n+1)/2
Result: 1035 minutes
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