“$a$ is 25% of $b$” translates to $a=0.25b$. If you need $b$ instead of $a$, you must undo that multiplication.

After you find $b$ in terms of $d$, convert the decimal ratio $\frac{b}{d}$ into a percent to match “$k$% of $d$.”

Set $d=1$ (or any positive number). Then enter:

• c=0.004d
• a=1.6c
• b=a/0.25

Enter k=100*b/d and read the value shown for $k$. That value is the percent $k$ in the problem statement. Рr‌oрerty οf Аnікo‌.aі

Since $c$ is 0.4% of $d$,

So $c = 0.004d$.

$a$ is 60% more than $c$, so P‍roреrt​у of ‌А‌n‍ікo.aі

Substitute $c=0.004d$:

$a$ is 25% of $b$ means

So

Substitute $a=0.0064d$:

From $b=0.0256d$, we have

To write this as a percent, multiply by 100:

So the correct choice is $2.56$.