Felix is now six times as old as Debbie. In twelve years time Felix will be two times as old as Debbie. How old are they
1 answer:
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Answer:
is the sum of positive integers between
(inclusive) and
(inclusive) that are not multiples of
and not multiples
.
Step-by-step explanation:
For an arithmetic series with:
as the first term,
as the last term, and
as the common difference,
there would be terms, where as the sum would be
.
Positive integers between (inclusive) and
(inclusive) include:
.
The common difference of this arithmetic series is . There would be
terms. The sum of these integers would thus be:
.
Similarly, positive integers between (inclusive) and
(inclusive) that are multiples of
include:
.
The common difference of this arithmetic series is . There would be
terms. The sum of these integers would thus be:
Positive integers between (inclusive) and
(inclusive) that are multiples of
include:
.
The common difference of this arithmetic series is . There would be
terms. The sum of these integers would thus be:
Positive integers between (inclusive) and
(inclusive) that are multiples of
(integers that are both multiples of
and multiples of
) include:
.
The common difference of this arithmetic series is . There would be
terms. The sum of these integers would thus be:
.
The requested sum will be equal to:
- the sum of all integers from
to
,
- minus the sum of all integer multiples of
between
and
, and the sum integer multiples of
between
- plus the sum of all integer multiples of
between
That is:
.
Answer:
31.85
Step-by-step explanation:
to subtract 30 percent from 45.50 just divide the percentage (30) by 100 subtract this value form 1 then multiply it by the initial value (45.50) so
final value = 45.50 x ( 1 - )
final value = 45.50 x ( 1 - 0.3)
final value = 45.50 x (0.7)
final value = 31.85
subtract 30% is the same as discount 30% this operation could be for example a 30% discount on 45.50
note: 0.3 can be found just by moving the decimal point 2 places to the left = 0.3 as a decimal